London deep-level shelters

The London deep-level shelters are eight deep-level air-raid shelters that were built under London Underground stations during World War II. == Background == Each shelter consists of a pair of parallel tunnels 16 feet 6 inches (5.03 m) in diameter and 1,200 feet (370 m) long. Each tunnel is subdivided into two decks, and each shelter was designed to hold up to 8,000 people.