The emergence of the Surrealist movement in Britain can be traced back to a singular event. On a hot summer day in 1936, the artist Sheila Legge walked across Trafalgar Square in a bridal gown, her head and face wrapped in red roses. Within hours, the mystery girl became the talk of the town, making headlines. In fact, Legge’s appearance was a P.R. stunt timed to the opening of the “London International Surrealist Exhibition” of 1936. In its latest exhibition, Whitechapel Gallery explores women such as Legge, who had pivotal but often overlooked roles in 20th-century Surrealism. Look for works by Claude Cahun, Diana Brinton Lee, Margaret Nash, and many others. —E.C.