Mithraeum

One notable exception requires a 40-minute drive south of Rome into the Alban Hills: The Marino Mithraeum, discovered in 2005, features a stunningly intact wall painting of the bonneted, spangled, pink-tights-clad man-god enacting the bull-stabbing scene.

The site was identified as a Mithraeum when in the last hours of the excavation the carved head of a handsome young god was found.

The Mithraeum incorporates a new daylit art gallery at ground level with an opening installation, Another View from Nowhen, by the Dublin artist Isabel Nolan.

The museum has a wonderful sculpture dug up from the Mithraeum — a post-party Bacchus and Pan, drunk off their immortal butts, propped up between a satyr and a maenad.

The London Mithraeum exhibition will open at the site in autumn 2017.