text: // 13.5.5 We create the tile layer that will be the background of our map.
  let light = L.tileLayer('https://api.mapbox.com/styles/v1/mapbox/light-v10/tiles/{z}/{x}/{y}?access_token={accessToken}', {
      attribution: 'Map data &copy; <a href="https://www.openstreetmap.org/">OpenStreetMap</a> contributors, <a href="https://creativecommons.org/licenses/by-sa/2.0/">CC-BY-SA</a>, Imagery © <a href="https://www.mapbox.com/">Mapbox</a>',
      maxZoom: 18,
      id: 'mapbox/light-v10',
      tileSize: 512,
      zoomOffset: -1,
      accessToken: API_KEY
  });
  
  // We create the dark view tile layer that will be an option for our map.
  let dark = L.tileLayer('https://api.mapbox.com/styles/v1/mapbox/dark-v10/tiles/{z}/{x}/{y}?access_token={accessToken}', {
  attribution: 'Map data © <a href="https://www.openstreetmap.org/">OpenStreetMap</a> contributors, <a href="https://creativecommons.org/licenses/by-sa/2.0/">CC-BY-SA</a>, Imagery (c) <a href="https://www.mapbox.com/">Mapbox</a>',
      maxZoom: 18,
      accessToken: API_KEY
  });
  
  // Create a base layer that holds both maps.
  let baseMaps = {
    Light: light,
    Dark: dark
  };
  
  // Create the map object with center, zoom level and default layer.
  let map = L.map('mapid', {
    center: [44.0, -80.0],
    zoom: 2,
    layers: [light]
  })
  
  // Pass our map layers into our layers control and add the layers control to the map.
  L.control.layers(baseMaps).addTo(map);
  
  // Accessing the Toronto airline routes GeoJSON URL
  let torontoData = " https://raw.githubusercontent.com/LleeMcD/Mapping_Earthquakes/main/torontoRoutes.json";
  
  // Create a style for the lines.
  let myStyle = {
    color: "#ffffa1",
    weight: 2
  }
  
  ///Grabbing our GeoJSON data.
  d3.json(torontoData).then(function(data) {
    console.log(data);
    L.geoJson(data, {
      style:myStyle,
      onEachFeature: function(feature, layer) {
        layer.bindPopup("<h3> Airline: " + feature.properties.airline + "</h3><hr><h3>Destination: "
        + feature.properties.dst + "</h3>");
      }  
    })
  // Creating a GeoJSON layer with the retrieved data.
  .addTo(map);
  });