Russian President Vladimir Putin has attended commemorations of the 80th anniversary of the Soviet victory over Nazi forces in the battle of Stalingrad.

Soviet Union dictator Joseph Stalin wanted the stations to be "palaces of the people" and subsequently brought in some of the best designers and architects around to bring his vision to life. Seven decades of historyCanadian photographer Christopher Herwig documents many of the stations along these metro systems, which cover 15 cities and six countries, in his new book "Soviet Metro Stations," a collaboration with author and journalist Owen Hatherley. Subterranean expeditionHerwig's subterranean expedition follows his previous book "Soviet Bus Stops," which saw him travel to 14 former Soviet countries and capture some of their most unusual bus stops. "Just as I loved hunting bus stops around the former Soviet Union, this was also amazing fun," he adds. "Soviet Metro Stations" by Christopher Herwig and Owen Hatherley is published by FUEL Publishing.