Central Europe

<!DOCTYPE html>
<head>
<meta charset="utf-8">
<script src="https://d3js.org/d3.v3.min.js"></script>
<style>

path {
  fill: none;
  stroke: #000;
  stroke-linejoin: round;
  stroke-linecap: round;
}

</style>
</head>

<body>

var canvas = d3.select("body").append("svg")
    .attr("width", 760)
    .attr("height", 760)

d3.json("data3.json", function (data) {

var group = canvas.selectAll("g")
    .data(data.features)
    .enter()
    .append("g")

var projection = d3.geo.mercator().scale(400).translate([200,600]);
var path = d3.geo.path().projection(projection);

var areas = group.append("path")
    .attr("d", path)
    .attr("class", "area")
    .attr("fill", "red")
    .attr("stroke", "red");

group.append ("text")
      .attr("x", function (d) { return path.centroid(d)[0]; })
       .attr("y", function (d) { return path.centroid(d)[1]; })
       .attr("text-anchor", "middle")
       .text(function (d) {return d.properties.name; })
       .attr("font-size", 8)

});

</script>
</body>

Modified http://d3js.org/d3.v3.min.js to a secure url

https://d3js.org/d3.v3.min.js