Christopher Wren commissioned himself to replace 50 churches after they burned down in the Great Fire of London (Wiki says 51 but that includes the interior refurbishment of Temple Church which was subsequently destroyed, so it does not count here).
Of the 50, 12 were demolished during Victorian times due to depopulation, 6 were demolished or substantially altered to make way for property development, 2 were taken down after being deemed structurally unsafe, 9 were destroyed during the blitz.
This Quest is to visit the remaining 22 Wren churches in the City of London that are largely unaltered or that have been faithfully restored. They are all Grade I listed buildings. They are all interesting. This is one of the few Quests that can be completed in a day.