(“Some 1,200 feet beneath the streets of Detroit,” writes Atlas Obscura, “runs 100 miles of subterranean roads over an area of more than 1,500 acres. It is the Detroit Salt Mine and as a Detroit industry it is older than automobiles. As a geological entity, this salt deposit is older even than the dinosaurs.” Source.)

A selection from #subterranean:

Deep Space Public Lighting, Chilean Copper-Gold Mines, Rare Earths Geopolitics, and iPhones as Portable Artificial Suns / A rogue Swiss tunnel digger's Subterranean Aeolian Farm / Speleotheraphy

In Chicago, don't call 811! / Our Solar Garden has rhizomatic subways bulbous with solar aviaries designed by Lequeu and Boullée. / In Mapping Abysses & The Catacombs of Rome in 3D, we call for a distributed network of autonomous laserscanning spelunking rovers to map out necropolises, ancient underground aqueducts, sewers, stormwater megatunnels, abandoned subway tunnels and transdimensional portals.

Three of our ultimate favorite posts: Deep-Sea Living in the Underground Tunnels of New York City / The Rhizotron of Illinois / Accessing the Wilderness, or: A Proposal for a National Park of Abandoned Gold Mines

A surprisingly high trafficked post: Dos personas en el centro de Sevilla / Cave Pharming / Call 811 to demand a National Subterranean Archive! / The Descent / From the Giant Guatemalan Sinkhole to The League of Super Amazing Landscape Architect Friends.

Negative Manhattan is marvelous! / Reinterred City / Tunnel-Digging as a Hobby / Hortus Conclusus / Helltown USA