Banpo Bridge

Listen first. Somewhere below you, water is moving. It is the slow, wide pull of the Han River, sliding past concrete piers on its way west toward the Yellow Sea. Above that sound comes the hum of traffic, a low steady roar of tyres on asphalt. And if you are here on a warm evening, there is a third sound: a hiss and a rush, as thousands of jets of water leap off the side of the bridge and fall back into the river.

This is Banpo Bridge. It links the southern district of Seocho with Yongsan on the northern bank, in the middle of Seoul. At first glance, it looks like one bridge among many. The Han is crossed by more than two dozen bridges inside the city alone. But this one has a secret, and you can see it from where you stand. Look closely at the lower edge of the structure... there is a second bridge underneath.

That lower bridge is called Jamsu Bridge. In Korean, "jamsu" means to submerge, or to dive. The name is not poetic. It is a plain description of the job. Jamsu Bridge was built in the 1970s, low and close to the water, and it was designed to go under. During the summer monsoon, when heavy rain swells the Han, the river rises over the deck. The bridge disappears for a while. Then the water drops, and it comes back.

Think about what that means for a city. Most bridges are built to stand above the worst flood. This one was built to accept the flood and survive it. Engineers kept the structure low and simple, so that fast water could pass over it without much resistance. When the river runs high, the city simply closes the crossing and waits. It is a very practical answer to a river that has always been stronger than the people living beside it.

In the early 1980s, Seoul added a second deck directly on top of Jamsu Bridge. This upper level became Banpo Bridge. The result is a double-decker crossing, rare among the river bridges of the city. Cars on the upper deck move fast and high above the water. Below, the old submersible bridge stays close to the current. Two eras of engineering sit one on top of the other, sharing the same line across the river.

To understand why Seoul built so many bridges in those decades, picture the city at the time. Seoul was growing at enormous speed. South Korea was going through the rapid economic rise that people often call the Miracle on the Han River. The south bank, once fields and sand flats, was filling with apartment blocks, offices and new roads. Each new bridge pulled the north and the south closer together. Banpo Bridge is one stitch in that very large piece of work.

For many years, this was simply a useful bridge. Then, in the late 2000s, the city gave it a new life after dark. Along both sides of the upper deck, engineers installed long rows of nozzles. They pump water straight from the Han, throw it out in wide arcs, and let it fall back into the river below. The installation is called the Moonlight Rainbow Fountain. Guinness World Records recognised it as the longest bridge fountain in the world.

Here is a detail many visitors miss. The water you see in the air is river water. It is not brought in from somewhere else. The fountain lifts the Han up, lights it, and returns it to the same current a moment later. So when you watch the show, you are really watching the river itself, raised into the air for a few seconds and then let go.

On evenings when the fountain runs, the show follows music. The jets rise and fall in time with the songs, and lights along the bridge turn the water blue, pink, green and gold. Because the jets fan out sideways from the deck, the best view is not from the bridge itself. It is from the riverbank below, looking up and across. From there, the whole length of the bridge becomes a long curtain of moving colour.

The southern bank is where most people gather. This is Banpo Hangang Park, one of the riverside parks that run along the Han through the city. On a warm night you will see families on picnic mats, couples on the steps by the water, cyclists rolling past on the long river path. People order fried chicken delivered straight to the grass. It is one of the most ordinary and most Seoul things you can do here: eat, talk, and watch the river.

Not far from the bridge, on the same southern bank, you may notice a cluster of unusual buildings sitting on the water itself. These are the floating islands, a group of structures moored in the river and used for events, cafés and exhibitions. At night they glow in changing colours, and their reflections stretch across the dark surface of the Han. Together with the fountain, they make this short stretch of riverbank one of the brightest places in the city after sunset.

If the river level allows it, walk onto the lower deck. Jamsu Bridge carries pedestrians and cyclists, and from here the Han feels very close. You can hear the water against the piers and smell the damp, mineral air of the river. Look up, and the upper deck runs over your head like a long concrete roof. On fountain nights, the falling water drums down beside you. It is a completely different experience from watching on the bank.

So take a moment before you leave. Notice the line where the old low bridge meets the newer one above it. Notice how close the water sits to the lower deck, and imagine it rising over the top in the summer rains. Watch the lights on the far bank, the towers of the north side, the slow current carrying the colours away. Then turn back toward the city... and listen once more for the sound of the river under everything.