Sitting on the secluded north eastern coast of Sardinia, the historic port city of Olbia was founded in the Roman age. The city's historic landmarks include the National Archaeology Museum, the Church of St Paul and the 12th century Basilica of San Simplicio church. Hire a car from Costa Smeralda Airport and explore the archaeological ruins close to Olbia and visit the Holy Well of Sa Testa, which is less than 10 minutes from the city. This monument is thought to have been built during the Bronze Age, and has 17 steps going underground.