Not the bridge in London — a natural limestone arch on the coast east of Torquay harbour, formed where the sea has eaten through a headland. Reach it on foot via the South West Coast Path from Meadfoot or Daddyhole Plain. The cliffs around it are red Devonian limestone, full of fossils, and the views back toward the harbour and out across Tor Bay are excellent.
Sturdy shoes recommended; the path is steep in places. About 30 minutes' walk from the harbour.