Approaching Kennington station at street level, the massive grey dome is easily overlooked, but glancing at the station from any sort of distance, or riding past it on a bus, it's hard to ignore.
The dome's delicate elegance is at odds with the rest of the station, and the surrounding area, so why is it there?
It's one of the only remaining station domes of a series that used to exist on stations on the City and South London Railway, now known as the Bank branch of the Northern line.
The line opened in 1890, and at the time Stockwell, Oval and Elephant & Castle also had the domes on. Here's what Stockwell looked like with the dome.
The purpose of the dome was to house the station's lift shaft and mechanism for the passenger lift which took passengers down to platform level.
However, in the 1920s, these other stations were all modernised, with major changes to the outside of the stations including the removal of the domes. Work was done underground at Kennington, but little was done to the surface building, so the dome remained. Clapham Common still retains its dome too.
To this day, Kennington station still has lifts, whereas they have been replaced by escalators in Stockwell and Oval. Elephant & Castle still has lifts, but many changes have been made to the original station, including the incorporation of the Bakerloo line and links to Elephant & Castle Shopping Centre, which opened in 1966. The dome has long since gone.