Q1: The mystery city is Montreal, Canada
Q2: The line in the d3 code that says "var svg = d3.select "contents"" tells d3 to display the geojson files on this webpage in the area where div id = contents.
Q3: We picked a value around 90 to rotate the view of the projection because the default view is 0,0, which centers the map at the prime meridian. Rotating the map view 90 degrees makes North America the focal point of the map, which is our prime area of interest.
Q4: To underline our labels in CSS, we would have to used the "text-decoration" command. You can use "text-decoration: underline" to underline a certain line of text. We would add this line of code to the .places-label bracket after the "fill" command to accomplish this.
Use the links above to download my geojson files. Data was collected from naturalearthdata.com. Created using QGIS and the d3 library.