Oura Cathedral (Oura Tenshudo)

Oura Cathedral, completed in 1864, is the oldest surviving Christian church building in Japan and was built by French missionary priests to serve the small foreign community newly permitted to reside in Nagasaki after the 1858 treaty ports opened. Its historical significance crystallized in 1865, when a group of local Japanese approached French priest Bernard Petitjean inside the church and revealed themselves as descendants of Kakure Kirishitan (hidden Christians) who had secretly preserved their faith for over two centuries since the 17th-century persecutions, an event known as the 'Discovery of Hidden Christians.' The wooden Gothic Revival structure, expanded and rebuilt in brick and plaster in 1879, features imported French stained glass, a vaulted timber ceiling, and a statue of the Virgin Mary above the entrance facing the harbor, a design intended to be visible to hidden Christian communities on offshore islands. The cathedral was damaged by the 1945 atomic bombing, located roughly 4 kilometers from the hypocenter, and subsequently restored; it was designated a National Treasure of Japan in 1953, the only church building to hold that status. The interior preserves 19th-century French-imported glasswork alongside a small museum wing displaying artifacts from the hidden Christian era and the 1865 discovery.