B6B5aw';

    var grayscale   = L.tileLayer(mbUrl, {id: 'mapbox/light-v9', tileSize: 512, zoomOffset: -1, attribution: mbAttr}),
    streets  = L.tileLayer(mbUrl, {id: 'mapbox/streets-v11', tileSize: 512, zoomOffset: -1, attribution: mbAttr});

    var map = L.map('map', {
      center: [52, 9],
      zoom: 6,
      layers: [grayscale, streets]
    });

    var baseLayers = {
      "Grayscale": grayscale,
      "Streets": streets
    };

    var overlays = {
      "Universities": universities 
    };

    L