Paris unclogs its sewers with giant balls of iron

Though it's been around since the Middle Ages, the sewer system beneath Paris won fame in the 19th century, when the city offered boat tours through the tunnels. This is also when an ingenious method for cleaning clogged tunnels was devised. It involves giant balls of iron and a lot of velocity. » 9/22/14 4:44pm 9/22/14 4:44pm

Explore More Than 3,000 Miles of Tunnels Beneath Montreal

Andrew Emond, a Montreal-based photographer, amateur geographer, and DIY gonzo spelunker of the city's sewers and lost rivers, has just re-launched his excellent website, Under Montreal. The revamped site now comes complete with a fascinating, interactive map of the city's subterranean streams, documenting Montreal's… » 3/04/14 4:20pm 3/04/14 4:20pm