In ancient Greek, petra means “rock,” but there’s more to this city than stone ruins. This former stronghold of the Arabian kingdom of Nabataean was carved directly into a rose-colored sandstone valley more than 2,000 years ago—and the rock-cut architecture and ingenious water systems are still much as they were millennia ago. Once you’ve explored Petra, take part in an age-old Jordanian desert tradition: safari through the Wadi Rum or “Valley of the Moon.”

Matera looks a lot like many other hill towns in Southern Italy. Explore the historic center, however, and you’ll find the Sassi of Matera, UNESCO–listed cave dwellings built into tufa limestone caves that offered shelter more than 9,000 years ago. Once maligned as the “shame of Italy” for the abject conditions of the poor living in the prehistoric dwellings, the town is now a mix of old and new—step inside the closely built sassi, and you'll find chic restaurants, churches, hotels, and more.

Pompeii is the closest you can get to real ancient city exploration. Once you get your ticket to the site, head down main street (decumanus maximus), and explore the houses and public sites that have been preserved in volcanic ash for some 2,000 years. There are still scenes of life and death here, from the erotic sculptures and frescoes in the House of the Vettii (and other villas) to the silhouettes of the city’s last inhabitants.

Inhabited since at least 3000 BC, Athens is among the oldest cities in the world. To see the evidence for this claim, look no further than the Acropolis citadel and ruins of the Parthenon, the Temple of Athena, and other historic buildings. Athens also serves as an excellent base for exploring another UNESCO site: Delphi, which boasts remarkably preserved ruins and sits on the southern slopes of Mount Parnassus.

Lying along the holy Ganges River, Varanasi (also called Benares) is one of India’s seven sacred cities and home to cremation sites for performing the funeral rituals thought to break the cycle of reincarnation. It is also, by some accounts, among the oldest continuously inhabited cities in the world. Varanasi is also one of the best places to experience Hindu traditions up close: You can explore riverfront temples, see sacred bathing sites, and visit ghats (age-old cremation grounds).

While it’s not technically a city, nor over 1,000 years old (it clocks in at a mere 900), Angkor Wat (“City of Temples”) is worth adding to this list because of its history, cultural importance, and artistry. The temple complex—which, at 400 acres (160 hectares), is roughly the size of a town—contains more than a thousand buildings, all of which are covered with carvings depicting Hindu stories and images of apsaras (celestial beings).

Choquequirao is a true adventurer’s destination. Lying 10,000 feet (3,000 meters) above sea level in the Peruvian Andes, the archaeological site comprises Inca temples, houses, baths, and agricultural terraces believed to have been built between the 15th and 16th centuries AD. It’s also more remote, and challenging to visit, than its more famous cousin, Machu Picchu: To reach the ruins, you need to commit to a difficult (but richly rewarding) 4-day round-trip trek.

The gates, mounds, and platforms of this ancient city in the Bolivian Altiplano, near Lake Titicaca, remain shrouded in mystery; we know very little about its construction and sudden abandonment. There’s even confusion about its true age. Early estimates placed it between 11,000 and 17,000 years old, but more accurate dating methods have put it at about 2,300. Some archeologists speculate that the grand UNESCO–listed ruins might be the remains of the ancient capital of the Tiwanaku Empire.

The last people to live in Montezuma were the Indigenous Sinagua of the southwestern US, and they abandoned the structures in the early 15th century. But the ruins—not actually a castle, but a 5-story village of multi-family dwellings—are thought to be much older than that and were likely first settled in the early 1100s by the Hohokam people. Together with the smaller Tuzigoot National Monument, the site comprises some of the best-preserved ruins in the American Southwest.