gordon travels through the underground railroad, a network of resistance base...

underground mine

a town underground

Underground alien city

alyx explains that she is part of an underground network known as the resistance and has been helping people escape the city on foot ; she also reveals that they have just developed a'better way'of moving them, which turns out to be a teleport.

underground spaceship

a canal boat in a london underground tube tunnel

Humans discovering an ancient city underground

graphic design for underground resistance record label

scene from the 1 9 1 2 science fiction film escape from new york

gopro footage of a battle between human soldiers and grey aliens with guns in a dark underground tunnel

Tony Hawk's Underground

an underground living room, cave walls, fluorescent lighting, underground, dingy, windowless

battle between human soldiers and grey aliens in a dark underground tunnel

movie still of the d'ni cavern, underground city, underground lake, cinematic, establishing shot, myst series

while attempting to rejoin the others, gordon and dog are separated from alyx by a collapsed ceiling, and gordon is forced to escape down the tunnel to ravenholm.

an underground New York City subway station platform designed by Zaha Hadid

an underground living room, cave walls, fluorescent lighting, underground, windowless

tower going underground

soviet underground underground underground underground underground mad max on zil artwork by greg rutkowski

there are also many old houses located along the coast, some being home to resistance members and escaped refugees, most having been raided by combine troops.

gordon reaches his destination, black mesa east, after a series of chases through the canals.

scene from the 1 9 1 1 science fiction film escape from new york

an underground school

a massive water leak in a london underground tube tunnel, water flooding everywhere