Long off-limits to Colombian tourists who remained trapped in their cities by the civil war, the countryside around Medellín is now secure and bustling with crowds. To the east lies the artificial reservoir Embalse Guatapé and the nearby Piedra del Peñol, a 200m-high granite monolith you can climb. From the top you'll find great views over the lake.
To the north of the city lies Santa Fe de Antioquia, a sleepy colonial town that was once the capital of the department. These days it attracts weekenders from Medellín looking to warm up – it's set at a mere 550m, and many hotels and restaurants have pools you can splash around in.
Three hours east of Medellín is Río Claro, a fantastic nature reserve with a peaceful river where you can go rafting or visit cathedral-sized caves full of bats.