The easiest way to identify St. Martin’s-in-the-Field Church is by its signature spire. But to truly experience what makes this 18th-century church special, visitors must venture down the stairs and elevator to the crypt. There, beneath the brick-vaulted ceiling and spread across the grave-lined floor, they’ll find a café. Café in the Crypt certainly wasn’t what the builders had in mind when they constructed St. Martin’s in 1726. But since most of the crypt’s bodies were removed in the 1800s, the space has been repurposed as a restaurant. Now the…