diff --git a/agenda/calendar.py b/agenda/calendar.py
index bc00d75..2dd7978 100644
--- a/agenda/calendar.py
+++ b/agenda/calendar.py
@@ -2,78 +2,106 @@
 
 import typing
 from datetime import timedelta
+import uuid
 
 from .event import Event
 
-event_type_color_map = {
-    "bank_holiday": "success-subtle",
-    "conference": "primary-subtle",
-    "us_holiday": "secondary-subtle",
-    "birthday": "info-subtle",
-    "waste_schedule": "danger-subtle",
+# A map to associate event types with a specific calendar ID
+event_type_calendar_map = {
+    "bank_holiday": "uk_holidays",
+    "conference": "conferences",
+    "us_holiday": "us_holidays",
+    "birthday": "birthdays",
+    "waste_schedule": "home",
+    "accommodation": "travel",
+    "market": "markets",
 }
 
-colors = {
-    "primary-subtle": "#cfe2ff",
-    "secondary-subtle": "#e2e3e5",
-    "success-subtle": "#d1e7dd",
-    "info-subtle": "#cff4fc",
-    "warning-subtle": "#fff3cd",
-    "danger-subtle": "#f8d7da",
-}
+# Define the calendars (categories) for TOAST UI
+# These will be passed to the frontend to configure colors and names
+toastui_calendars = [
+    {"id": "default", "name": "General", "backgroundColor": "#00a9ff"},
+    {"id": "uk_holidays", "name": "UK Bank Holiday", "backgroundColor": "#28a745"},
+    {"id": "us_holidays", "name": "US Holiday", "backgroundColor": "#6c757d"},
+    {"id": "conferences", "name": "Conference", "backgroundColor": "#007bff"},
+    {"id": "birthdays", "name": "Birthday", "backgroundColor": "#17a2b8"},
+    {"id": "home", "name": "Home", "backgroundColor": "#dc3545"},
+    {"id": "travel", "name": "Travel", "backgroundColor": "#ffc107", "color": "#000"},
+    {"id": "markets", "name": "Markets", "backgroundColor": "#e2e3e5", "color": "#000"},
+]
 
 
-def build_events(events: list[Event]) -> list[dict[str, typing.Any]]:
-    """Build list of events for FullCalendar."""
+def build_toastui_events(events: list[Event]) -> list[dict[str, typing.Any]]:
+    """Build a list of event objects for TOAST UI Calendar."""
     items: list[dict[str, typing.Any]] = []
-
     one_day = timedelta(days=1)
 
     for e in events:
         if e.name == "today":
             continue
+
+        # Determine the calendar ID for the event, defaulting if not mapped
+        calendar_id = event_type_calendar_map.get(e.name, "default")
+
+        # Handle special case for 'accommodation'
         if e.name == "accommodation":
             assert e.title and e.end_date
-            item = {
-                "allDay": True,
-                "title": e.title_with_emoji,
-                "start": e.as_date.isoformat(),
-                "end": (e.end_as_date + one_day).isoformat(),
-                "url": e.url,
-            }
-            items.append(item)
-
-            item = {
-                "allDay": False,
-                "title": "check-in: " + e.title,
-                "start": e.date.isoformat(),
-                "url": e.url,
-            }
-            items.append(item)
-            item = {
-                "allDay": False,
-                "title": "checkout: " + e.title,
-                "start": e.end_date.isoformat(),
-                "url": e.url,
-            }
-            items.append(item)
-
+            # All-day event for the duration of the stay
+            items.append(
+                {
+                    "id": str(uuid.uuid4()),
+                    "calendarId": calendar_id,
+                    "title": e.title_with_emoji,
+                    "start": e.as_date.isoformat(),
+                    "end": (e.end_as_date + one_day).isoformat(),
+                    "isAllday": True,
+                    "raw": {"url": e.url},
+                }
+            )
+            # Timed event for check-in
+            items.append(
+                {
+                    "id": str(uuid.uuid4()),
+                    "calendarId": calendar_id,
+                    "title": f"Check-in: {e.title}",
+                    "start": e.date.isoformat(),
+                    "end": (e.date + timedelta(hours=1)).isoformat(),
+                    "isAllday": False,
+                    "raw": {"url": e.url},
+                }
+            )
+            # Timed event for check-out
+            items.append(
+                {
+                    "id": str(uuid.uuid4()),
+                    "calendarId": calendar_id,
+                    "title": f"Checkout: {e.title}",
+                    "start": e.end_date.isoformat(),
+                    "end": (e.end_date + timedelta(hours=1)).isoformat(),
+                    "isAllday": False,
+                    "raw": {"url": e.url},
+                }
+            )
             continue
 
+        # Handle all other events
+        start_iso = e.date.isoformat()
         if e.has_time:
-            end = e.end_date or e.date + timedelta(minutes=30)
+            end_iso = (e.end_date or e.date + timedelta(minutes=30)).isoformat()
         else:
-            end = (e.end_as_date if e.end_date else e.as_date) + one_day
+            end_date = (e.end_as_date if e.end_date else e.as_date) + one_day
+            end_iso = end_date.isoformat()
+
         item = {
-            "allDay": not e.has_time,
+            "id": str(uuid.uuid4()),
+            "calendarId": calendar_id,
             "title": e.title_with_emoji,
-            "start": e.date.isoformat(),
-            "end": end.isoformat(),
+            "start": start_iso,
+            "end": end_iso,
+            "isAllday": not e.has_time,
         }
-        if e.name in event_type_color_map:
-            item["color"] = colors[event_type_color_map[e.name]]
-            item["textColor"] = "black"
         if e.url:
-            item["url"] = e.url
+            item["raw"] = {"url": e.url}
         items.append(item)
+
     return items
diff --git a/templates/calendar.html b/templates/calendar.html
index 31067ce..fb6013c 100644
--- a/templates/calendar.html
+++ b/templates/calendar.html
@@ -7,69 +7,18 @@
   <link href="{{ url_for("static", filename="bootstrap5/css/bootstrap.min.css") }}" rel="stylesheet">
   <link rel="icon" href="data:image/svg+xml,<svg xmlns=%22http://www.w3.org/2000/svg%22 viewBox=%220 0 100 100%22><text y=%22.9em%22 font-size=%2290%22>📅</text></svg>">
 
-  <script async src="{{ url_for("static", filename="es-module-shims/es-module-shims.js") }}"></script>
-
-    <script type='importmap'>
-      {
-        "imports": {
-          "@fullcalendar/core": "https://cdn.skypack.dev/@fullcalendar/core@6.1.9",
-          "@fullcalendar/daygrid": "https://cdn.skypack.dev/@fullcalendar/daygrid@6.1.9",
-          "@fullcalendar/timegrid": "https://cdn.skypack.dev/@fullcalendar/timegrid@6.1.9",
-          "@fullcalendar/list": "https://cdn.skypack.dev/@fullcalendar/list@6.1.9",
-          "@fullcalendar/core/locales/en-gb": "https://cdn.skypack.dev/@fullcalendar/core@6.1.9/locales/en-gb"
-        }
-      }
-    </script>
-    <script type='module'>
-      import { Calendar } from '@fullcalendar/core'
-      import dayGridPlugin from '@fullcalendar/daygrid'
-      import timeGridPlugin from '@fullcalendar/timegrid'
-      import listPlugin from '@fullcalendar/list'
-      import gbLocale from '@fullcalendar/core/locales/en-gb';
-
-      // Function to save the current view to local storage
-      function saveView(view) {
-          localStorage.setItem('fullCalendarDefaultView', view);
-      }
-
-      // Function to get the saved view from local storage
-      function getSavedView() {
-          return localStorage.getItem('fullCalendarDefaultView') || 'dayGridMonth';
-      }
-
-      document.addEventListener('DOMContentLoaded', function() {
-        const calendarEl = document.getElementById('calendar')
-        const calendar = new Calendar(calendarEl, {
-          locale: gbLocale,
-          plugins: [dayGridPlugin, timeGridPlugin, listPlugin ],
-          themeSystem: 'bootstrap5',
-          firstDay: 1,
-          initialView: getSavedView(),
-          viewDidMount: function(info) {
-              saveView(info.view.type);
-          },
-          headerToolbar: {
-            left: 'prev,next today',
-            center: 'title',
-            right: 'dayGridMonth,timeGridWeek,timeGridDay,listWeek'
-          },
-          nowIndicator: true,
-          weekNumbers: true,
-          eventTimeFormat: {
-            hour: '2-digit',
-            minute: '2-digit',
-            hour12: false,
-          },
-          events: {{ fullcalendar_events | tojson(indent=2) }},
-          eventDidMount: function(info) {
-            info.el.title = info.event.title;
-          },
-        })
-        calendar.render()
-      })
-
-    </script>
-
+  <!-- TOAST UI Calendar CSS -->
+  <link rel="stylesheet" href="https://uicdn.toast.com/calendar/latest/toastui-calendar.min.css" />
+  <style>
+    /* Custom styles to better integrate with Bootstrap */
+    .toastui-calendar-layout {
+      border: 1px solid #dee2e6;
+      border-radius: 0.375rem;
+    }
+    #calendar-header {
+      margin-bottom: 1rem;
+    }
+  </style>
 </head>
 
 {% set event_labels = {
@@ -91,16 +40,6 @@
 }
 %}
 
-{%set class_map = {
-  "bank_holiday": "bg-success-subtle",
-  "conference": "bg-primary-subtle",
-  "us_holiday": "bg-secondary-subtle",
-  "birthday": "bg-info-subtle",
-  "waste_schedule": "bg-danger-subtle",
-} %}
-
-
-
 {% from "navbar.html" import navbar with context %}
 <body>
   {{ navbar() }}
@@ -108,7 +47,7 @@
   <div class="container-fluid mt-2">
     <h1>Agenda</h1>
     <p>
-      <a href="/tools">&larr; personal tools</a>
+      <a href="/tools">← personal tools</a>
     </p>
 
   {% if errors %}
@@ -126,8 +65,25 @@
   | <a href="{{ url_for(request.endpoint, markets="hide") }}">Hide all</a>
   </div>
 
-  <div class="mb-3" id="calendar"></div>
+  <!-- Header for calendar controls -->
+  <div id="calendar-header" class="d-flex justify-content-between align-items-center mt-3">
+      <div class="btn-group" role="group">
+          <button type="button" class="btn btn-primary" id="prevBtn">Prev</button>
+          <button type="button" class="btn btn-primary" id="nextBtn">Next</button>
+          <button type="button" class="btn btn-outline-primary" id="todayBtn">Today</button>
+      </div>
+      <h3 id="calendar-title" class="mb-0"></h3>
+      <div class="btn-group" role="group">
+          <button type="button" class="btn btn-outline-primary" id="monthViewBtn">Month</button>
+          <button type="button" class="btn btn-outline-primary" id="weekViewBtn">Week</button>
+          <button type="button" class="btn btn-outline-primary" id="dayViewBtn">Day</button>
+      </div>
+  </div>
 
+
+  <div class="mb-3" id="calendar" style="height: 80vh;"></div>
+
+  {#
   <div class="mt-2">
     <h5>Page generation time</h5>
     <ul>
@@ -137,11 +93,137 @@
     {% for name, seconds in timings %}
     <li>{{ name }} took {{ "%.1f" | format(seconds) }} seconds</li>
     {% endfor %}
-
     </ul>
   </div>
+  #}
 
   </div>
+
+      
+<!-- TOAST UI Calendar JS -->
+  <script src="https://uicdn.toast.com/calendar/latest/toastui-calendar.min.js"></script>
   <script src="{{ url_for("static", filename="bootstrap5/js/bootstrap.bundle.min.js") }}"></script>
+  
+  <script>
+    document.addEventListener('DOMContentLoaded', function() {
+        const Calendar = tui.Calendar;
+        const container = document.getElementById('calendar');
+
+        // --- Configuration ---
+        const calendars = {{ toastui_calendars | tojson }};
+        const events = {{ toastui_events | tojson }};
+
+        function getSavedView() {
+            return localStorage.getItem('toastUiCalendarDefaultView') || 'month';
+        }
+        
+        function saveView(view) {
+            localStorage.setItem('toastUiCalendarDefaultView', view);
+        }
+
+        const options = {
+            defaultView: getSavedView(),
+            useDetailPopup: true,
+            useCreationPopup: false,
+            calendars: calendars,
+            week: {
+                startDayOfWeek: 1, // Monday
+                taskView: false,
+                eventView: ['time'],
+                showNowIndicator: true,
+            },
+            month: {
+                startDayOfWeek: 1, // Monday
+                // We've removed `visibleWeeksCount: 6` to allow the calendar
+                // to dynamically show 4, 5, or 6 weeks as needed.
+            },
+            timezone: {
+                zones: [{
+                    timezoneName: Intl.DateTimeFormat().resolvedOptions().timeZone
+                }]
+            },
+            template: {
+                allday(event) {
+                    return `<span title="${event.title}">${event.title}</span>`;
+                },
+                time(event) {
+                    return `<span title="${event.title}">${event.title}</span>`;
+                },
+            },
+        };
+
+        const calendar = new Calendar(container, options);
+        calendar.createEvents(events);
+
+        // --- Event Handlers ---
+        calendar.on('clickEvent', ({ event }) => {
+            if (event.raw && event.raw.url) {
+                window.open(event.raw.url, '_blank');
+            }
+        });
+        
+        calendar.on('afterRenderEvent', () => {
+            const currentView = calendar.getViewName();
+            saveView(currentView);
+            updateCalendarTitle();
+        });
+
+
+        // --- UI Control Logic ---
+        const prevBtn = document.getElementById('prevBtn');
+        const nextBtn = document.getElementById('nextBtn');
+        const todayBtn = document.getElementById('todayBtn');
+        const monthViewBtn = document.getElementById('monthViewBtn');
+        const weekViewBtn = document.getElementById('weekViewBtn');
+        const dayViewBtn = document.getElementById('dayViewBtn');
+        const calendarTitle = document.getElementById('calendar-title');
+        
+        function updateCalendarTitle() {
+            const tzDate = calendar.getDate();
+            const nativeDate = tzDate.toDate();
+            
+            const year = nativeDate.getFullYear();
+            const monthName = nativeDate.toLocaleDateString('en-GB', { month: 'long' });
+            
+            calendarTitle.textContent = `${monthName} ${year}`;
+        }
+
+        // --- CORRECTED NAVIGATION LOGIC ---
+        prevBtn.addEventListener('click', () => {
+            const currentDate = calendar.getDate().toDate();
+            // Go to the previous month
+            currentDate.setMonth(currentDate.getMonth() - 1);
+            // **Crucially, set the day to the 1st to align the view**
+            currentDate.setDate(1);
+            calendar.setDate(currentDate);
+            updateCalendarTitle();
+        });
+
+        nextBtn.addEventListener('click', () => {
+            const currentDate = calendar.getDate().toDate();
+            // Go to the next month
+            currentDate.setMonth(currentDate.getMonth() + 1);
+            // **Crucially, set the day to the 1st to align the view**
+            currentDate.setDate(1);
+            calendar.setDate(currentDate);
+            updateCalendarTitle();
+        });
+        
+        todayBtn.addEventListener('click', () => {
+            calendar.today();
+            updateCalendarTitle();
+        });
+
+        monthViewBtn.addEventListener('click', () => calendar.changeView('month'));
+        weekViewBtn.addEventListener('click', () => calendar.changeView('week'));
+        dayViewBtn.addEventListener('click', () => calendar.changeView('day'));
+        
+        // Initial setup
+        updateCalendarTitle();
+    });
+  </script>
+
+    
+      
 </body>
 </html>
diff --git a/web_view.py b/web_view.py
index 6e7da53..05d7fcd 100755
--- a/web_view.py
+++ b/web_view.py
@@ -107,7 +107,6 @@ async def index() -> str:
         events=events,
         get_country=agenda.get_country,
         current_trip=get_current_trip(today),
-        fullcalendar_events=calendar.build_events(events),
         start_event_list=date.today() - timedelta(days=1),
         end_event_list=date.today() + timedelta(days=365 * 2),
         render_time=(time.time() - t0),
@@ -129,11 +128,13 @@ async def calendar_page() -> str:
     if markets_arg != "show":
         agenda.data.hide_markets_while_away(events, data["accommodation_events"])
 
+    # Use the new function to build events and pass both calendars and events
     return flask.render_template(
         "calendar.html",
         today=now.date(),
         events=events,
-        fullcalendar_events=calendar.build_events(events),
+        toastui_events=calendar.build_toastui_events(events),
+        toastui_calendars=calendar.toastui_calendars,
         **data,
     )
 
@@ -374,6 +375,7 @@ def past_conference_list() -> str:
         fx_rate=agenda.fx.get_rates(app.config),
     )
 
+
 @app.route("/accommodation")
 def accommodation_list() -> str:
     """Page showing a list of past, present and future accommodation."""