This striking Greek Revival church has a tower designed to imitate the Temple of the Winds in Athens, a portico with six Ionic columns and a wing decorated with caryatids like the Erechtheion on the Acropolis. When it was completed in 1822 this was the most expensive new church to have been built in London since St Paul's Cathedral. Head to the atmospheric Crypt Gallery to see the latest art exhibition or drop in to a free lunchtime recital on a Thursday (1.15pm).
Within the porch you can see a large tablet in memory of the 31 people who lost their lives nearby in the King's Cross Tube station fire of November 1987. The church is named after a 4th-century Roman boy martyred for his faith at age 14.