diff --git a/docs/config.rst b/docs/config.rst
index 9909f13..200c5b2 100644
--- a/docs/config.rst
+++ b/docs/config.rst
@@ -1248,6 +1248,29 @@ BiomeOverlay
 
             BiomeOverlay(biomes=[("Forest", (0, 255, 0)), ("Desert", (255, 0, 0))])
 
+HeatmapOverlay
+    Color the map according to when a chunk was last visited. The color for Timestamps 
+    between t_invisible and t_full will be interpolated between 0 and 255.
+    This RenderPrimitive might require use of the forcerender option. 
+    Otherwise the Overlay might not get updated for not visited chunks (resulting in them
+    always being the brightest color, as if recently visited).
+
+    **Options**
+    
+    t_invisible
+        The timestamp when the overlay will get invisible. The default is 30 days ago.
+    
+    t_now
+        The timestamp when the overlay will be fully visible. The default is today.
+    
+    Example::
+
+        HeatmapOverlay(
+            t_invisible=int((t_now - timedelta(days=2)).timestamp()),
+            t_full=int(t_now.timestamp()),
+        )
+
+
 Defining Custom Rendermodes
 ---------------------------
 
diff --git a/overviewer_core/rendermodes.py b/overviewer_core/rendermodes.py
index 7ae67fe..75e7ce0 100644
--- a/overviewer_core/rendermodes.py
+++ b/overviewer_core/rendermodes.py
@@ -12,6 +12,7 @@
 #
 #    You should have received a copy of the GNU General Public License along
 #    with the Overviewer.  If not, see <http://www.gnu.org/licenses/>.
+from datetime import datetime, timedelta
 
 from PIL import Image
 from . import textures
@@ -231,6 +232,17 @@ class BiomeOverlay(Overlay):
         'alpha'  : ('an integer value between 0 (transparent) and 255 (opaque)', None),
     }
 
+class HeatmapOverlay(Overlay):
+    t_now = datetime.now()
+    name = "overlay-heatmap"
+    options = {
+        't_invisible': (
+            'the timestamp when the overlay will get invisible (e.g. 1 month go)',
+            int((t_now - timedelta(days=30)).timestamp())
+        ),
+        't_full': ('the timestamp when the overlay will be fully visible (e.g. now)', int(t_now.timestamp())),
+    }
+
 class Hide(RenderPrimitive):
     name = "hide"
     options = {
diff --git a/overviewer_core/src/primitives/overlay-heatmap.c b/overviewer_core/src/primitives/overlay-heatmap.c
new file mode 100644
index 0000000..cd7666b
--- /dev/null
+++ b/overviewer_core/src/primitives/overlay-heatmap.c
@@ -0,0 +1,93 @@
+/*
+ * This file is part of the Minecraft Overviewer.
+ *
+ * Minecraft Overviewer is free software: you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as published
+ * by the Free Software Foundation, either version 3 of the License, or (at
+ * your option) any later version.
+ *
+ * Minecraft Overviewer is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General
+ * Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with the Overviewer.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <math.h>
+#include "overlay.h"
+
+typedef struct {
+    /* inherits from overlay */
+    RenderPrimitiveOverlay parent;
+    int t_invisible;
+    int delta_t;
+} RenderPrimitiveHeatmap;
+
+static void get_color(void* data, RenderState* state,
+                      uint8_t* r, uint8_t* g, uint8_t* b, uint8_t* a) {
+    RenderPrimitiveHeatmap* self = (RenderPrimitiveHeatmap*)data;
+    long mtime;
+    float _value_f;
+    char value;
+    PyObject *mtime_pyobj;
+
+    // Set default values (will get overridden based on self->mode)
+    *r = 255;
+    *g = 0;
+    *b = 0;
+
+    // Get the chunk modified time
+    mtime_pyobj = PyObject_CallMethod(state->regionset, "get_chunk_mtime", "ii", state->chunkx, state->chunkz);
+    if (mtime_pyobj == NULL) {
+        *a = 0;
+        return;
+    }
+    mtime = PyLong_AsLong(mtime_pyobj);
+
+    // Convert the time to a value in the range [0,255] based on t_invisible and delta_t
+    _value_f = (mtime - self->t_invisible) / (float)self->delta_t;
+    value = _value_f <= 0 ? 0 : (_value_f >= 1 ? 255 : 255*_value_f);
+    *a = value;
+}
+
+static bool
+overlay_heatmap_start(void* data, RenderState* state, PyObject* support) {
+    RenderPrimitiveHeatmap* self;
+    int t_full;
+
+    /* first, chain up */
+    bool ret = primitive_overlay.start(data, state, support);
+    if (ret != false)
+        return ret;
+
+    /* now do custom initializations */
+    self = (RenderPrimitiveHeatmap*)data;
+    self->parent.get_color = get_color;
+
+    if (!render_mode_parse_option(support, "t_invisible", "I", &(self->t_invisible)))
+        return true;
+
+    if (!render_mode_parse_option(support, "t_full", "I", &t_full))
+        return true;
+
+    self->delta_t = t_full - self->t_invisible;
+    return false;
+}
+
+static void
+overlay_heatmap_finish(void* data, RenderState* state) {
+    /* chain up */
+    primitive_overlay.finish(data, state);
+}
+
+RenderPrimitiveInterface primitive_overlay_heatmap = {
+    "overlay-heatmap",
+    sizeof(RenderPrimitiveHeatmap),
+    overlay_heatmap_start,
+    overlay_heatmap_finish,
+    NULL,
+    NULL,
+    overlay_draw,
+};