Java's Biggest Buddhist Temple Has No Mortar, and That Is Why It Still Stands

From a distance, Borobudur looks like a mountain rising from the river plains in the shadow of a great volcano. Up close, it is nine stacked platforms, 35 meters high with a rounded shrine at the peak, raised by the rulers of Mataram, the early kingdom that ruled central Java.

The design is an enormous mandala, an important geometric shape in Buddhism used to describe the form of the universe. From above, the mandala spans about as much ground as two soccer fields. On the ground, it guides pilgrims up through concentric walkways and stairways carved from black volcanic stone, bordered by almost 3,000 sculpted panels and 500 statues of the Buddha created by the kingdom's most skilled artisans.

What holds it all together is what is missing. The builders used no mortar or cement. They cut about 2 million pieces of volcanic rock so each piece grips its neighbors without glue. In one of the most earthquake prone places on Earth, that loose fit has been a strength, allowing the temple to ride out countless tremors and shifting ground over the past thousand years.

Rain was the other enemy. Java gets drenching seasonal monsoon rains, so the builders fitted Borobudur with more than 100 drainage spouts, each sculpted to look like a giant or sea dragon. When it rained, water poured from their mouths and away from the stone.

The symbolism would have been clear to medieval Javanese. Their stories said the gods had placed Java's mountains to hold the floating island steady. The king was placing his own mountain to show that his reign would last. As Raden Sokmono, the archaeologist who led the temple's modern restoration, put it, Borobudur is a prayer in stone. Heritage worker Gerard Bolla described it as a landscape for pilgrims seeking inner peace, with volcanoes glowing red at night beyond a ring of mountains made from the same volcanic stone.

It worked. Built as an artificial mountain, it survived like one.