When creating many geographic circles (e.g. for visualizing graduating radii on a map), calling d3.geo.circle multiple times will create overlapping great circles, which may not be desired.
Compare with the simple fix shown at Non-Overlapping Geographic Circles.
Modified http://d3js.org/d3.v3.min.js to a secure url
Modified http://d3js.org/d3.geo.projection.v0.min.js to a secure url
Modified http://d3js.org/topojson.v1.min.js to a secure url
Changed /mbostock/raw/4090846/world-50m.json to a local referenece
https://d3js.org/d3.v3.min.js
https://d3js.org/d3.geo.projection.v0.min.js
https://d3js.org/topojson.v1.min.js