Aachen

Aachen is the 13th-largest city in North Rhine-Westphalia and the 27th-largest city of Germany, with around 264,000 inhabitants. It is the western-most major city in Germany, lying approximately 61 km (38 mi) west of Cologne and Bonn, directly bordering Belgium in the southwest, and the Netherlands in the northwest. The city lies in the Meuse–Rhine Euroregion and is the seat of the district of Aachen (Städteregion Aachen). The once Celtic settlement was equipped with several thermae in the course of colonization by Roman pioneers settling at the warm Aachen thermal springs around the 1st century. After the withdrawal of the Roman troops, the vicus Aquae Granni was Frankized around the 5th century, by which it came under Merovingian and later Carolingian rule. With the completion of the Carolingian Palace of Aachen at the transition to the 9th century, Aachen was constituted as the main royal residence of the Frankish Empire ruled by Charlemagne. Because of that, the city is sometimes called the "cradle of Europe". After the Treaty of Verdun, the city was within the borders of Middle Francia, until it became part of East Francia after the Treaty of Meerssen (870).