Yeouido, the island whose piers now launch every Han River dinner cruise, began the twentieth century as an airfield. Colonial engineers laid Korea's first runway across its sandflats in 1916. Cattle grazed the strip between flights. The island was not rebuilt into offices, parkland and embankment until the 1970s. The river is older than the city that claims it. Early records call it the Hansu; Seoul knows it simply as the Hangang, 한강. The Baekje kingdom set its first capital, Wiryeseong, on the southern bank, and for centuries the water was crossed at naru — ferry landings at Mapo, Nodeul and Dongjak, where flat-bottomed boats carried grain, salt and soldiers. Bridges replaced them slowly. Twenty-seven now span the river inside the capital, and the words gangbuk and gangnam, north and south of the water, still divide Seoul more sharply than any administrative line. Much of what passengers see from the deck is engineered. Between 1982 and 1986 the Hangang Comprehensive Development Project dredged the channel, raised concrete embankments and held the river at a constant depth ahead of the 1986 Asian Games and the 1988 Olympics. The riverside parks date from that decade, as does regular passenger sailing; Han River dinner cruise tickets did not exist before it, the channel being too shallow and too silted for scheduled evening traffic. Two structures anchor the sightline. The 63 Building, completed in 1985 on Yeouido's eastern edge, rises 249 metres behind gold-tinted glass and held the title of Korea's tallest for nearly two decades; at sunset it behaves like a mirror set on end. Downstream, the Moonlight Rainbow Fountain, installed on Banpo Bridge in 2009, pushes water from hundreds of nozzles along roughly 1,140 metres of deck, lit in sequence once darkness falls. Seoul river cruise tours trade on that contrast — a Joseon-era waterway framed by 1980s concrete and twenty-first-century lighting. The evening illumination along the banks is municipal policy rather than decoration, coordinated bridge by bridge. A photograph taken from a Han River dinner cruise tour tends to flatten what is in fact a layered record: a floodplain, an airstrip, an Olympic project and a working commuter city, all held in a single frame.