The Royal Garrison Church in Penny Street, Portsmouth was built around 1212 by the Bishop of Winchester, as part of a hospital complex, which also provided accommodation for pilgrims. After the Reformation, it started to decay and was turned into an ammunition dump, hence the name. The church was extensively restored in 1871, but was bombed out during the Blitz.
It is now managed by English Heritage, who are currently undertaking a second restoration. The church is scheduled to reopen to visitors in June 2022. Entry, when the church is open, is free. The postcode is PO1 2NJ. The church is three-quarters of a mile from Portsmouth Harbour station, and is served by bus routes 1, 16, 19 and 700.