leaflet-map.js

map = L.map("transitmap", {
            center: [ 34.730225, -86.585944 ],    // Huntsville, AL
            zoom: 15
        });
        
L.tileLayer("http://korona.geog.uni-heidelberg.de/tiles/roads/x={x}&y={y}&z={z}", {
    attribution: "&copy; <a href='http://giscience.uni-hd.de/'>GIScience Research Group @ University of Heidelberg</a> © <a href='http://www.openstreetmap.org/copyright'>OpenStreetMap</a>",
    maxZoom: 20
}).addTo( map );