So you booked a holiday to Rome at one of the hottest times of the year and are now considering spending the rest of your trip spreadeagle on your bed under your hotel room’s AC unit.

Fortunately, salvation is at hand: the Eternal City is built of on top of a vast network of ancient underground dwellings, cemeteries and churches, all of which are well worth visiting, and many degrees cooler than the surface temperature.

Here are five of the best sites to escape the heat in Rome while soaking in some history and culture – as with most of the city’s attractions, you’ll want to book in advance to make sure you secure a slot.

Domus Aurea

Located under the Parco del Colle Oppio, within striking distance of the Colosseum, Nero’s ‘Golden Palace’ remained buried for hundreds of years until it was rediscovered by accident during the 15th century.

The tour takes you deep underground, where you’ll have the opportunity to see original frescoes and mosaics and participate in a virtual reality experience showing how the sprawling complex would have looked 2,000 years ago.

Where: Via della Domus Aurea, 00184 Roma

When: Friday-Sunday, 9.15am-5pm

How much: €18 full price, €2 for EU citizens 18-25, under-18s go free for entry without tour. €8 per person extra for guided tour with VR experience. 

Basilica of San Clemente

A unique tiered ruin spanning three levels and hundreds of years, the Basilica di San Clemente is an opulent 12th century basilica above a 4th century church converted from the house of a Roman nobleman, with 11th century frescoes.

Below this is a first century complex featuring, among other things, the ruins of Roman homes, a part of the ancient city’s imperial mint, a Mithraic temple, and a stream of water running through a still-operational ancient Roman pipe.

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Where: Via di S. Giovanni in Laterano, 45, 00184 Roma

When: Monday-Saturday, 9am-12pm and 2pm-5.30pm; 12pm-5.30pm on Sundays and holidays

How much: €10 full price booked online in advance or €12 at the door, €5 for students under 26, free for under-16s accompanied by at least one adult.

Catacombs of San Callisto

Rome is full of labyrinthine networks of underground tombs, and none is more famous than the Catacombs of San Callisto, the Roman Church’s official cemetery in the third century.

At this burial site on the ancient Appian Way outside the city centre, you’ll find the Crypt of the Popes, which once contained the remains of nine popes and eight bishops.

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It’s worth noting that the bones were removed some time ago; for a spookier experience, you might want to consider Rome’s ‘Bone Church’, the Capuchin Crypt, where the walls are lined with skulls, bones, and the mummified remains of monks in their robes – a true memento mori.

Where: Via Appia Antica, 110, 00179 Roma

When: Every day except Wednesdays, 9am-12pm and 2pm-5pm

How much: €10 full price, €7 for children aged 7-16, free entry for children under 6.

Domus Romane of Palazzo Valentini

In front of Trajan’s forum, seven metres below the opulent 16th century Palazzo Valentini palace, sits a complex of two luxurious 4th century Roman villas, discovered as recently as 2005 during excavation works.

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Visitors can explore the underground site via an impressive augmented reality tour that uses projected images to bring the ruins to life.

Where: Foro Traiano, 85, 00186 Roma

When: Every day except Tuesdays, 10am-6.30pm; special open evenings Friday-Sunday, Jul 5 to Sept 22nd, 7.00 pm-11.00 pm

How much: €12 full price, €8 for children aged 6-17, free for children under 6, plus €1.50 reservation fee.

Case Romane del Celio

Tucked away on the approach to Rome’s pretty but well-hidden Villa Celimontana park just around the corner from the Colosseum, you’ll find these well-preserved ancient Roman houses that once served as a place of worship for early Christians.

The complex consists of about 20 rooms spread over two villas underneath a 4th century basilica. Though you can buy an audio guide for €5, visitors tend to recommend booking a guided tour; these are only available in English via a group reservation.

Where: Clivo di Scauro, 00184 Roma

When: Every day except Tuesdays and Thursdays, 10am-3pm.

How much: €8 full price, €6 for children aged 6-14 and groups of over 12 people, free for children under 6, plus €2 per person booking fee.