Where: Crystal Palace Subway
After years of work, Crystal Palace Subway has finally been restored and it's absolutely stunning. The subway first opened in 1865 to provide an easy pedestrian route for first class passengers arriving at the train station to get to the palace. Its design is typical of the Victorian era, with mosaic-style red brick adorning a series of imposing arches, and it's now been restored to its original glory in time for its 160th anniversary.
The Grade II listed construction has been through a lot — it survived a huge fire that engulfed the palace complex in 1936 and was later used as an air raid shelter during World War II. After the High Level Crystal Palace station closed in the 1950s the subway fell into disrepair, but thankfully this refresh makes it a worthy destination for architecture fans once again. For now, visiting is restricted to monthly open days, but entry is free and no advance booking is necessary; check online for dates.