Cabo San Juan del Guía is a beautiful cape with a knockout beach. It's also by far the most crowded area of the park, although lack of road access deters casual day-trippers. The area has a restaurant and a campsite, with hammocks and cabins, in a spectacular lookout on a rock in the middle of the beach. It's possible to spend a very atmospheric night here. Swimming is also possible most of the time, but don't go in too deep.
Cabo San Juan del Guía
Top choice in Parque Nacional Natural Tayrona