Vaulted concrete underground tunnel of sewer, heating duct or water supply system
Keywords
tunnel,
duct,
underground,
sewer,
water,
heating,
supply,
vaulted,
pipeline,
system,
main,
pipe,
corridor,
passage,
inside,
subterranean,
warm,
tube,
abandoned,
concrete,
heat,
deep,
line,
ventilation,
dark,
temperature,
construction,
dirty,
factory,
homeless,
habitation,
industrial,
circulation,
industry,
plumbing,
aqueduct,
engineering,
urban,
air,
rust-eaten,
exploring,
steel,
metal,
power,
collector,
valva,
mystery,
technical