Luxembourg City

Luxembourg City takes 2 days: the old town and the Bock Casemates (UNESCO World Heritage), a network of tunnels and galleries carved into the rock, on one day; the Grand Ducal Palace and the Kirchberg financial district on the other. May-September has the best weather for walking the green gorges surrounding the historic center. It's one of Europe's most expensive capitals, reflecting its role as home to EU institutions and an international banking hub. Unlike other capitals, it has had 100% free public transport since 2020, the first country in the world to implement it nationwide.