 geoPath)
            .attr("class", "countries")
            .style("fill", d => countryColor(geoPath.area(d)))
            .style("stroke", d => d3.rgb(countryColor(geoPath.area(d))).darker());
        
        d3.select("svg").selectAll("circle").data(cities)
          .enter()
          .append("circle")
            .attr("class", "cities")
            .attr("r", 3)
            .attr("cx", d => projection([d.x,d.y])[0])
            .attr("cy", d => projection([d.x,d.y])[1]);

        var graticule = d3.