The 2000‐year history of the City of Cologne began in 57 BC, when Julius Caesar conquered everything up to the Rhine during the Gallic Wars. The Rhine River played an important role as the border between the Romans to the west and the Germanic tribes to the east. It was supposed to remain that way for the next 2000 years. In the year 50 AD, Cologne received city status under the name Colonia Claudia Ara Agrippinensium (CCAA). By the end of the 1st century AD, Cologne was the capital of the Province of Germania Inferior. By the middle of the 5th century, the Franks had finally conquered the CCAA. From the 10th to 16th centuries, Cologne evolved to become the largest and richest city in Germany. Approximately 40,000 people lived within about 4 km2 (1.5 mi2). With this population, Cologne was by far the largest German city. Residents of Cologne claimed it had as many churches as there were days in a year and wanted to build the largest church in the world. Almost 300 years after the first stone was laid in 1248, the construction of the dome began (1560) and the cathedral still was not finished. With the discovery of the Americas, trade moved to the seas and Cologne lost its place as a trade crossroads. At the end of the 18th century, Napoleon and his soldiers took the Rhineland and the next 20 years brought modernization to Cologne. The Congress of Vienna gave the Rhineland to the Prussians. Industrialization began in Cologne in the middle of the 19th century and Cologne became one of the leading economic centers in Germany and the third‐largest city. This lead to the complete destruction of the city in WWII; 95% of the city’s downtown area was destroyed in 1945. Reconstruction went quickly and without real city planning. Today the municipal boundaries of Cologne enclose 400 km2 (155 mi2). With a population of about 1,000,000, Cologne is now the fourth‐largest city in Germany.