Located in London, I measured the RTT or round trip time to 574,691 random webservers and plotted the times on the globe.
Discovery was done with masscan, measurements using hping and plotting with an old Python script I've revived and enhanced.
~~This is part of the next writeup on my blog, with which I will be posting any of the code I've used.~~
That was experimenting, the actual graph shown is the other way around, so it shows the real differences, not just compared to lightspeed (ie I forgot to remove the '1 -' from the label)