The Hindhead Tunnel, opened in 2011, is part of the 4-mile (6.4 km) dual-carriageway that replaced one of the last remaining stretches of single-carriageway on the A3 road which connects the cities of London and Portsmouth. It was built to bypass the village of Hindhead in Surrey. At 1.14 miles (1.83 km) in length, the tunnel is the longest non-estuarial road tunnel in the United Kingdom, and takes the road beneath the Devil's Punch Bowl, a Site of Special Scientific Interest.