Visit the ancient city of Anuradhapura on a full moon day and the past feels anything but distant.
Buddhist pilgrims dressed in white walk barefoot on dusty paths. Saffron-robed monks chant at dawn. Foreign visitors – from Taiwan to Canada – join local worshipers in rituals that have been performed here, largely without interruption, for more than 2,000 years.
Located on the north-central plains of Sri Lanka, Anuradhapura was the island’s first major capital. Today, it remains one of the holiest cities in the Buddhist world, known as the first place to adopt Buddhism outside of India. Within its vast archaeological park are monasteries, tanks and stupas that are among the most ambitious religious monuments ever built.
Above them rises the immense bubble dome of the Jetavanaramaya – a structure so large that when it was completed in the early 4th century AD, it ranked as the third largest man-made building on Earth, surpassed only by the Great Pyramids of Giza.
Completed around 301 CE using approximately 93.3 million baked mud bricks, the stupa originally stood at approximately 122 meters (400 feet), making it one of the tallest structures in the ancient world.
Restoration work carried out in 2010 at Abhayagiri Dagoba, another stupa at Anuradhapura. -John Elk III/The Image Bank RF/Getty Images
Today, after centuries of collapse, abandonment and restoration, the Jetavanaramaya stands about 71 meters (233 feet) – still monumental, but little more than half its original height. Even so, it remains the largest brick structure by volume ever built.
Its mass is so vast that archaeologists estimate its bricks could build a three-foot-tall wall stretching from London to Edinburgh – or from New York to Pittsburgh.
However, outside Sri Lanka, Jetavanaramaya is little known. Unlike the pyramids, history was not permanently visible. Jungle growth, changing religious priorities and selective preservation gradually buried both the monument and much of its story, leaving one of the greatest engineering achievements of the ancient world largely forgotten.
Lost – and rediscovered
Jetavanaramaya refers not only to the stupa itself, but also to the heart of a vast monastic complex known as the Jetavana Vihara, designed to house hundreds of monks. Every structure in the complex was oriented towards the stupa, ensuring that monks stepping outside their residences would face it first – a daily reminder of devotion and cosmological order.
“About 200 monks lived here,” explains Godamune Pannaseeha, a bespectacled monk and senior archeology officer in Anuradhapura and one of the leading contemporary experts on Jetavanaramaya.
“People came to offer clothes, books, food – everything – to earn merit,” says Godamune Pannaseeha, senior archeology officer in Anuradhapura. – Justin Calderon
“People came to offer clothes, books, food – everything – to gain merit,” he says, pointing to the stupa’s lower terraces where offerings were once made as he made a slow, clockwise circuit around its base. “This was a living religious city.”
From the beginning, however, Jetavanaramaya was controversial. It was built on land traditionally associated with the Maha Vihara, the orthodox Theravada Buddhist institution, without the consent of its monks. Later, the complex became associated with the Sagalika sect, which followed Mahayana-leaning doctrines.
No Mahayana chronicles from ancient Sri Lanka have survived. Today, Sri Lanka remains a predominantly Theravada Buddhist nation. As a result, much of Jetavanaramaya’s history—including the political and doctrinal tensions surrounding its creation—must be reconstructed indirectly, leaving historians with incomplete and sometimes contested versions.
Ancient engineering on a massive scale
The technical challenges involved in building the Jetavanaramaya were immense. Unlike the stone pyramids of Egypt, this colossal structure was built almost entirely of mud bricks—a material far more vulnerable to erosion and collapse.
“To replace one block of stone, you need 10 bricks,” says Anura Manatunga, senior professor of archeology at the University of Kelaniya in Sri Lanka. “That means millions and millions of bricks had to be prepared, transported and laid with precision.”
Anuradhapura remains one of the holiest cities in the Buddhist world. -Alex Ogle/AFP/Getty Images
This is what Jetavanaramaya looked like in 1965. – Harvey Meston/Archive Photos/Getty Images
Archaeologists have identified ancient brick kilns in and around Anuradhapura, confirming large-scale brick production in the region. None, however, can yet be definitively linked to the Jetavanaramaya or securely dated to the early 4th century.
Moving this volume of material would have required tremendous organization – and work.
Although there are no records that specifically mention animals at Jetavanaramaya, historians believe that elephants and bullock carts were almost certainly used, as they were at other important sites in Sri Lanka, including Ruwanwelisaya, the city’s most sacred stupa, built centuries earlier in 140 BC.
Elephants probably carried bricks and cleared earth for the foundations, a technique used in traditional construction on the island until relatively recent times.
It was even more outdated in 1926 when this photo was taken. – Print Collector/Hulton Archive/Getty Images
Scaffolding would have been largely based on bamboo, tied with coir rope made from coir and jungle creepers. Metal was used sparingly, reserved for tools rather than structural elements.
Built to last
Jetavanaramaya reflects the height of ancient Sri Lankan engineering knowledge. Its massive hemispherical shape distributes weight efficiently, while its foundations have been carefully prepared. Ancient chronicles describe how builders flooded excavated land to observe absorption—a rudimentary but effective form of soil testing.
A fallen section of the stupa reveals more ingenuity. Pannaseeha points to an empty, cylindrical chamber in the ruins that suggests an early understanding of ventilation.
Despite this sophistication, time has taken its toll. Earthquakes, monsoon rains and centuries of neglect have caused sections of the stupa to collapse. The last major renovation took place in the 12th century during the reign of King Parakramabahu I.
More recent restoration efforts introduced cement into some of the outer layers—a decision archaeologists now believe may have accelerated the deterioration rather than prevented it. The original mortar used to lay the bricks was composed of a mixture of finely crushed dolomite, limestone, sifted sand and clay.
Excavations also uncovered relic coffins embedded in the stupa at various structural levels. These held sacred relics and ritual repositories, reinforcing Jetavanaramaya’s role not only as an architectural feat, but also as a sacred structure built from the inside out.
Among the most significant finds related to the Jetavanaramaya are the gold panels depicting Bodhisattva images and inscribed with sections of the Prajñāpāramitā sutra, a foundational text of Mahayana Buddhism. Now held at the National Museum in Colombo, the panels were written in Sanskrit using ancient local scripts.
They provide rare material evidence of Mahayana practice in ancient Sri Lanka, suggesting that Jetavana was once a center of cosmopolitan Buddhist thought, connected by doctrine and trade routes to India and beyond.
A peak of mystery
Standing at the base of the stupa, Pannaseeha gestures to the damaged spire.
“Historical writings say that a diamond once crowned the peak, possibly to deflect lightning during monsoon storms,” he says.
The spire itself is unusual. “It resembles a tower,” he notes—a shape that some scholars believe may reflect technological influence from the Roman or wider Mediterranean world, transmitted through Indian Ocean trade networks.
“Historical writings say that a diamond once crowned the peak, possibly to deflect lightning during monsoon storms,” says Pannaseeha. – Justin Calderon
Whether symbolic or functional, much about its construction remains unclear.
“We can see small remnants of the decorative motifs, including that of the Naga, a form of cobra hood,” adds Pannaseeha, pointing to intricate carvings at the base. “But we still don’t know exactly how they were fixed in place.”
Grandeur and devotion
The sheer scale of Jetavanaramaya invites comparison with Ruwanwelisaya, the nearby gleaming white stupa, which today has far greater religious significance for Sri Lanka.
Ruwanwelisaya is believed to enshrine some of Buddhism’s most revered relics, including some of the Buddha’s remains. It remains the center of pilgrimage and national religious life.
Although smaller than the Jetavanaramaya in its original form, the Ruwanwelisaya has been continuously maintained and today stands taller than the truncated structure of the Jetavana, rising to more than 100 meters (328 feet).
Where Jetavanaramaya represents architectural boldness and doctrinal debate, Ruwanwelisaya embodies devotional continuity.
Eetalawetunwawe Gnanathilaka Thero, one of the country’s most respected religious figures and head monk at Ruwanwelisaya, has seen a steady increase in foreign visitors to Anuradhapura in recent years.
“First there was civil war, then a pandemic,” he says. “But in the last two years, there has been a noticeable increase in foreign visitors to our holy city.”
Travelers are welcome to observe – and participate in – any of the nine daily puja rituals, the first beginning at dawn.
Anuradhapura was the first great capital of the island of Sri Lanka. – Thilina Kaluthotage/NurPhoto/Getty Images
Visit on a full moon day and thousands of pilgrims arrive waiting patiently to enter Ruwanwelisaya and Sri Maha Bodhi, the temple surrounding a sacred fig tree believed to have grown from a sapling of the tree under which the Buddha attained enlightenment.
The last of its kind
Perhaps the most striking fact about the Jetavanaramaya is that nothing like it has been built again. For nearly 700 years after its completion, no stupa of a comparable scale was attempted in Sri Lanka.
“This was the last truly gigantic stupa,” says Manatunga. “Not only here, but even in Southeast Asia, later builders adopted the same bubble-like form, but never on this scale.”
Jetavanaramaya today stands as evidence of an ancient society capable of organizing manpower, materials and engineering knowledge on a scale that rivaled any civilization of its time.
That it remains relatively unknown beyond Sri Lanka may be one of history’s great oversights – a reminder that some of the most extraordinary achievements of the ancient world were not carved in stone but fashioned from earth, devotion and human ingenuity.
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