The cathedral is built in a style called Romanesque Revival, which means it was designed to look like the ancient stone churches of medieval Europe, with round arches, thick walls and tall bell towers. The builders used a pale stone called 'La Turbie stone', which gives the building its bright, creamy white colour that glows in the Mediterranean sunshine.
Inside the cathedral is a remarkable altarpiece — a large painted panel — made in the 1500s by a Niçois artist called Louis Brea. It shows many figures in bright colours and is considered one of the finest examples of this kind of painting in the whole region. The building also has beautiful stained-glass windows that fill the interior with coloured light on sunny days.
The cathedral choir has a long musical tradition. The Choir of Monaco has been singing in this building for over 500 years, and boys and girls from the area still train there today to become accomplished singers. On special occasions, the choir fills the stone vaulted space with music that echoes beautifully off the ancient walls.