An east London highlight, the Grotto is the 18th century survival of one of the grandest houses ever built in England, Wanstead House. Built on the edge of a lake between 1760 and 1764, the Grotto cost £2,000 and was spectacular. Lined with fossils, crystals and carved stone it was an entertainment space as well as an exotic eyecatcher in a period when grottoes and follies were in high fashion. After the house was demolished and it was opened to the public it was much visited and admired.

However in 1884, a fire broke out in a storeroom and because the lake in front was being cleaned and was empty, there was no water to extinguish it. It was badly damaged, with only the outer walls remaining.