The Dell in Grays is a modest Victorian villa with an extraordinary distinction: it is one of the first houses in Britain to have been built using concrete as the primary structural material. The house dates from around 1901 and is listed for its architectural and historical significance. It looks from the outside like an ordinary late Victorian house, which was rather the point — the builder wanted to demonstrate that concrete could produce a building indistinguishable from conventional construction.
The house is a private residence and not open to the public, but it is worth a look from the street as a footnote in the history of construction. It is in the residential streets north of the town centre, about 15 minutes' walk from the High Street.