the.com/metro
a city's bloodstream, hurtling strangers underground while pretending the silence is normal
deepest stationKyiv's Arsenalna sits 105 meters underground
oldest lineLondon's opened in 1863, steam-powered and choking
busiest systemTokyo moves billions of riders yearly
bomb sheltersMoscow's deep stations doubled as wartime refuges
rat ecologyunderground rats evolve distinct populations per station