Take a deep dive into the city and discover the history of a little-known world, that of the casemates. They are a vast network of underground tunnels and galleries partly built and carved into the rock of Luxembourg City. Originally built as a defensive system in the 17th and 18th centuries, they later served as bomb shelters during World War II and for other purposes. Today, they are a major tourist attraction, offering visitors a glimpse into the city's rich history.