A look around Southwark Cathedral. (Or to give it its full name, the Cathedral Church of St Saviour and St Mary Overie).
It’s believed to be the first gothic church in London, with the oldest part of the building dating back to the early 1200s. It seems to have a checkered history of falling into disrepair and restoration throughout its life.
It’s located close to London Bridge underground station (at the southern end of London Bridge) and is in easy walking distance of other attractions such as Tate Modern, the Golden Hinde and H.M.S. Belfast.
It really is worth a visit, an island of tranquility in the middle of a very busy part of London.