Founded by the Celts on the banks of the River Danube, Bratislava, Slovakia’s capital, is one of those European cities whose history and buildings amassed over the centuries make it an essential destination. In the city, the castle, Cathedral of St. Martin, Mirbach Palace (a Rococo masterpiece) or the ruins of Devin Castle on the banks of the Danube contribute to the romantic and antiquated atmosphere of this pearl of eastern Europe.