Example
<div id="map" style="height: 500px;"></div>
Stylesheet
<link href="assets/lib/leaflet/leaflet.css" rel="stylesheet">
<link href="assets/lib/leaflet.markercluster/MarkerCluster.css" rel="stylesheet">
<link href="assets/lib/leaflet.markercluster/MarkerCluster.Default.css" rel="stylesheet">
Javascript
<script src="assets/lib/leaflet/leaflet.js"></script>
<script src="assets/lib/leaflet.markercluster/leaflet.markercluster.js"></script>
<script src="assets/lib/leaflet.tilelayer.colorfilter/leaflet-tilelayer-colorfilter.min.js"></script>