In Paris, old limestone quarries fan out in a deep and intricate web under many neighborhoods, mostly in the southern part of the metropolis. Here, a fire thrower named Louis spins light at a gathering in one old quarry. Nearly all of the more than 180 miles of quarry tunnels are off-limits, but parties happen anyway.
Travelers crowd the platforms at Churchgate Railway Station in Mumbai—the largest city in India—in this photo shot on assignment for National Geographic magazine's special series, Population 7 Billion.
Colorfully painted windows—927 in all—distinguish the Ministry of Communications and Information headquarters in Singapore. Built in 1934, the six-story building originally served as a police station and barracks. It became a national monument in 1998 and is known today as the Old Hill Street Police Station.
The San Francisco-Oakland Bay Bridge is a work-in-progress in this picture by amateur photographer L.A. Sanchez, awarded a prize for the image in 1935. Construction on the bridge began in 1933 and was completed in 1936.
The city of Baia Mare in northwestern Romania is known for its mining history and well-preserved medieval remnants. Here, a quiet street is captured by National Geographic Your Shot contributor Cristi Niculescu.