Tam Coc and Bich Dong

At Tam Cốc, the river will not go around the mountains. It runs straight through the heart of them, not once but three times.

The river is called the Ngô Đồng. From a small bamboo boat drifting slowly on the water, a traveler sees rice fields on both banks, and beyond them, limestone mountains rising straight up, gray-green and silent. In places, the mountains press so close to the water that the boat seems to be passing through a giant gorge. And yet, right at the foot of those cliffs, the rice fields still turn green and then gold with the seasons. Small hamlets still tuck themselves into the hollows between the peaks.

This is Tam Cốc and Bích Động. The area is part of the Tràng An Landscape Complex. In 2014, UNESCO inscribed Tràng An as a mixed World Heritage site, valued for both its nature and its culture. Visitors playfully call this area Ha Long Bay on land, because the rocky peaks here rise out of rice fields, not out of the sea.

The name Tam Cốc simply means three caves. The first is Hang Cả. After it come Hang Hai and Hang Ba. All three were made by the Ngô Đồng, which patiently wore its way through the heart of the mountains.

When the boat reaches the mouth of the first cave, a sheer wall of rock rises straight ahead. The stone ceiling drops lower and lower. The darkness thickens around the sides of the boat, and the soft lapping of water against the rock suddenly sounds clearer than ever. At this point, people sometimes hold their breath without noticing. Then a streak of light appears ahead. It grows wider, the cave opens out on the far side of the mountain, and the landscape spreads out again, as if a curtain had just been raised.

Three caves mean three times into the dark and three times back into the light. Hang Cả, then Hang Hai. Then Hang Ba. Each time the boat comes out of the darkness, the mountains, the sky and the fields look as if they are being seen for the very first time. The whole boat trip, there and back, takes about two hours.

In the ripening season, there is even a festival here with a lovely name. It is called Sắc vàng Tam Cốc, Tràng An, which means the golden color of Tam Cốc and Tràng An. One year, the festival's rice fields covered 22 hectares, turning golden between the gray cliffs. From the boat, the whole view is a single shimmering color. That same year, right near Hang Hai, people even made a picture out of rice. It covered more than 10,000 square meters, which is larger than a soccer field.

There is a reason the mountains here stand so straight, and it lies in the rock itself. Tràng An is a tower karst landscape in the humid tropics: limestone mountains that water and time have carved for millions of years. The upright peaks and the sunken, enclosed valleys bear the marks of a very long geological process. So do the networks of underground caves and the waterways that connect them.

In this same limestone country, people left traces of their lives more than 30,000 years ago. For all of these reasons, UNESCO inscribed Tràng An under three criteria, numbers five, seven and eight. The first is the mark of people living alongside the rocky peaks over many thousands of years. The second is natural beauty of a rare kind. The third is the geological story of the earth, written on every peak.

Off the boat, the trip carries on over land. The same circuit takes in Thái Vi Temple and Tiên Cave, and then Bích Động Pagoda. Each place keeps its own layer of the story.

Thái Vi Temple stands in the hamlet of Văn Lâm. It carries the memory of the Trần dynasty in the 13th century. The temple honors emperors of that dynasty, among them Trần Thái Tông and Trần Thánh Tông. It also honors other figures of the dynasty, which led the nation through three wars against the Mongol armies. The Vũ Lâm area all around was once a strategic base of the Trần.

In 1994, the temple was listed as a national historical and cultural site. Inside, there is a great deal to look at closely. There are stone pillars more than 3 meters tall, and a dragon courtyard. There is the gate called Ngũ Đại môn, and a two-story bell tower with eight roofs.

Then comes Bích Động Pagoda, one of the most beautiful old pagodas in the Tràng An area. In 1705, two monks named Trí Kiên and Trí Thể made their way to this place. They repaired the site and enlarged it. In time, three pagodas came to stand here, one above the other up the mountainside. They are the Lower Pagoda, the Middle Pagoda and the Upper Pagoda.

Nearly 70 years later, Lord Trịnh Sâm came to visit. The year was 1774. He was one of the Trịnh lords, a noble family who dominated northern Vietnam. He looked at the rocky peaks and the caves, the river and the lush green trees. Then he gave the place the name Bích Động, which means green cave. It was a simple name, and yet it has stayed with the pagoda for more than 200 years, right up to today.

What is unusual about Bích Động is that the pagoda does not just stand beside the mountain. It also lives inside it. The Middle Pagoda sits halfway up, half tucked into a rock cave and half open to the sky. From the Lower Pagoda to the Middle Pagoda, visitors climb about 120 stone steps. From the Middle Pagoda, nearly 40 more steps lead up to the Upper Pagoda. The Upper Pagoda is dedicated to Quan Âm, the bodhisattva of compassion.

Here, Buddhist architecture and the karst mountains cannot be pulled apart. The pagoda is part of the mountain, and the mountain is just as much a part of the pagoda.

For a long time, people have passed down another name for Bích Động by word of mouth. They call it Nam thiên đệ nhị động, the second most beautiful cave under the southern sky. It is a cultural title, not a scientific ranking. But the title alone shows how deeply people of the past loved this land.

From the Upper Pagoda, a whole picture opens out. A river winds through the rice fields, and the mountains rise in layer after layer all the way to the horizon. Somewhere behind those peaks, the Ngô Đồng still slips quietly into the heart of the mountain. A small bamboo boat is drifting into the darkness of Hang Cả, and on the far side of the mountain, the light is waiting for it.