the.com/underground
Where dirt keeps every secret, every root, and most of the good ideas.
deepest mineSouth Africa's gold reaches nearly 4 km down
hidden cityTurkey's Derinkuyu sheltered 20,000 people below ground
fungal webUnderground fungi networks link trees for miles
first metroLondon's Underground opened in 1863, steam-powered
buried lifeMicrobes thrive kilometers below Earth's surface