London, England, United Kingdom
Post Office Underground Railway Opened 5 December 1927. The first automatic electric railway and the only postal railway in the world, providing a unique solution to the problem of transporting large volumes of mail across a capital city. — Mount Pleasant Post Office, 151 Mount Pleasant Road, N17
Listen to the audio guide for Blue plaque № 8969 Free on WIP — starts by itself when you arrive, even with the screen off