Köprülü Canyon cuts through the western Taurus Mountains about 50km north of Side, where the Köprü River has carved a gorge with walls reaching 400 metres in places. The national park that surrounds it is the main white-water rafting destination in the Antalya region, and on a summer day the river fills with bright rafts and the riverbank with operators handing out helmets and paddles. The lower section is gentle enough for first-timers and families; the upper stretches have rapids that ask for a bit more nerve.
Two Roman bridges still span the gorge almost perfectly intact after roughly two thousand years. The Oluk Bridge and the Bugrum Bridge arch high over the water and are still used by local traffic, which is the kind of quiet engineering miracle that Turkey scatters around without much fuss. Either makes a good place to stop, look down at the green water, and take the measure of the canyon before you get on it.
Most visitors come on an organised day trip from Side or Manavgat that bundles transport, equipment, and a riverside lunch — usually grilled trout at one of the restaurants built out over the water. The drive up through pine forest and rising rock walls is worth the journey on its own, and it is the same road that climbs to the remote ancient city of Selge on the heights above. If you would rather stay dry, you can walk the canyon rim, picnic by the bridges, or push on up to the Selge ruins for the long view back down the gorge.