London is the capital and largest city of England and the United Kingdom. The city stands on the River Thames in the south-east of England, at the head of its 50-mile (80 km) estuary leading to the North Sea. The City of London, London's ancient core and financial centre − an area of just 1.12 square miles (2.9 km2) and colloquially known as the Square Mile − retains boundaries that closely follow its medieval limits.

Luxembourg is a landlocked country in Western Europe. It is bordered by Belgium to the west and north, Germany to the east, and France to the south. With an area of 2,586 square kilometres (998 sq mi), it is one of the smallest sovereign states in Europe.