Best known as the capital of Charlemagne's Frankish empire, today's Aachen sits at the juncture where Germany meets the Netherlands (where the Dutch know it as Aken) and Belgium (where Walloons call it Aix-la-Chapelle). But Aachen's history pre-dates even 8th-century Charlemagne. Roman soldiers dating back to the 1st century AD cherished its hot springs (they called it Aquis-Granum). Aachen Cathedral, northern Europe's oldest and a UNESCO World Heritage Site, is the city's main attraction.