A mysterious Roman cult temple may become the newest UNESCO World Heritage Site

When the UNESCO World Heritage Committee meets in July 2026 to review potential candidates, Türkiye is almost certain to gain a new entry, one that is shedding light on a mysterious ancient war cult so secretive that its rites were thought lost to the world. If all goes according to plan, Zerzevan Castle and Mithraeum will become the fifth UNESCO World Heritage Site in the Tigris and Euphrates River valleys, fueling interest in the country’s little-visited southeastern region.

“Recent excavations at Zerzevan Castle revealed one of the best preserved and perhaps oldest Mithras sanctuaries within the Roman empire, which has caused a sensation both domestically and internationally,” says Aytaç Coșkun, professor of archaeology at Dicle University and excavation director of the Zerzevan Castle site. The site has been on the UNESCO World Heritage tentative list since 2020.

“Although numerous Mithras temples are known to have existed throughout the world, very few have survived to the present day,” says Coșkun. “Ceremonies were conducted in great secrecy, and information about the beliefs was shared only with those belonging to the faith, so archaeological finds are of great importance in helping us understand this mysterious sect."

What has been discovered

Since excavations began in 2014, archaeologists have uncovered some 60 acres of the castle, including a 60-foot-high watchtower and remnants of massive city walls that once towered as high as 45 feet. With only a portion of the hilltop site explored, researchers have documented a church, administrative buildings, storage rooms, and residential areas. Among the revelations announced this year: A remarkably sophisticated water storage and transport system that Coșkun terms “an engineering marvel,” featuring 63 massive underground cisterns and channels carrying water beyond the castle walls.

But it’s the Mithras temple, discovered in 2017, and its revelations, that have intrigued the world. Originating in Iran and dedicated to an ancient Indo-Persian sun god, the militaristic religion—open only to men—swept the Roman world between the first and fourth century C.E. before being banned with the spread of Christianity. Images of bulls carved into the walls, sacrificial hooks hanging from the ceiling, and a bowl and pool designed to catch blood attest to the prevalence of ritual animal sacrifice.

“Visitor interest in Zerzevan Castle and Mithraeum has increased significantly in recent years as excavation and restoration continue,” says Birol İnceciköz, director general of culture heritage and museums. “If Zerzevan Castle and the Mithraeum are inscribed on the UNESCO World Heritage Site, there will be a significant increase in visitor numbers to the region.” 

With those burgeoning visitor numbers in mind, the site is undergoing improvements including a new visitor’s center opening this spring.

(Why Türkiye’s Black Sea coast is the Mediterranean alternative to visit in 2026)

New reasons to visit ancient sites

The neolithic archaeological site of Karahan Tepe will soon be far more accessible to visitors with the addition of raised boardwalks, paved paths, and a protective roof, scheduled for completion in late 2026. And Sayburç, another site in the expanding network, will also gain a new museum to display—among other finds—a 12,000-year-old human statue unearthed in September 2025 that’s stunning scholars with its expressive detail.

New finds emerge every season from the 25 archaeological sites so far identified in the network now known as Taş Tepeler, or the Stone Mounds, with many of the most impressive pillars, statues, and implements collected in the Sanliurfa Archaeological Museum. How did Neolithic people, outfitted only with small chipped flint and obsidian tools, carve and erect these towering statues and structures? And, why and how were they used? 

The answers are upending scientists’ understanding of our origins, revealing that 12,000 years ago—7,000 years before Stonehenge and 9,000 years before the Egyptian pyramids—the residents of Taş Tepeler were the first to establish large settlements, plant crops, and create monumental places of worship. Then, as mysteriously as they arrived, they walked away, burying their achievements under deep layers of sand and rock.

What else to see and do

It takes little imagination to picture merchants, artisans, and haggling shoppers thronging the limestone-walled markets of Mardin, where soap-makers, silversmiths, painters, and textile weavers still sit behind tables piled high with wares. Honey-colored mansions and 12th-century mosques and madrasahs stair-step up the steep streets, while the area’s Syriac Christian heritage remains in practice at the Deyrulzafaran Monastery, open to daily tours.

Laying claim as the birthplace of Abraham, Şanliurfa bustles with pilgrims and families visiting the caves, shrines, and carp-filled pools that mark episodes in his legend. Tucked deep within the arched courtyard of a 16th century caravansary, Gümrük Han cafe serves menengiç coffee, demonstrating the traditional Ottoman technique of brewing Sanliurfa’s specialty drink of ground pistachios.

Named a UNESCO City of Creative Gastronomy for its smoky kebabs, pistachio paste delicacies, and extra-flaky baklava, Gaziantep has become even better known for the Zeugma Mosaic Museum, which logged its highest-ever visitor numbers in 2025. Here, raised walkways carry visitors over a vast expanse of intricately tiled mosaic floors dating to the 2nd century C.E., which were rescued from rising waters during the construction of the Birecik Dam. In the old city, hammers ring a tune through the maze-like Coppersmith Bazaar, which has been in continuous operation since camels knelt to load up its spices, hand-shaped metalwork, and colorful leather shoes.

The basalt walls of Diyarbakır loom over the Tigris River, protecting a fourth-century walled city, the entirety of which is a UNESCO World Heritage Site. Historically a crossroads with trade links to Iran, Anatolia, the Caucasus, and the Black Sea, Diyarbakır is a cultural mélange, evident in its bustling markets and signature dishes such as meftune, a tangy-sweet stew of lamb, eggplant, and aromatic sumac, slow-cooked in a clay pot and served with raisin-studded pilaf.

This spring will also see the return of the overnight Mesopotamia Express, which makes the 653-mile journey from Ankara to Diyarbakır in 24 hours, with stops at numerous historic sites.

Symbolic in its forging of a stronger connection between the country’s urbane capital and the less developed southeast, the launch of the Mesopotamia Express suggests something far deeper: The return of visitors to this cradle of civilization.