This is one of the most visited attractions in the principality, primarily because it contains the tomb of the former princess of Monaco, Grace Kelly, who first gained fame as an American film actress, winning an Oscar for The Country Girl. Many of the ruling Grimaldis are also buried here, mostly recently Prince Rainier III.

Dedicated to Saint Nicholas, the cathedral was consecrated in 1911. It stands on the site of the first parish of Monaco dating from 1252. In addition to the Grimaldi tombs, seek out the huge organ containing almost 5,000 pipes and the white Carrara marble altar.