- Castle of the Dukes of Brittany

Begun by Francis II, the Golden Crown Tower (Tour de la Couronne d'Or) was completed by Anne of Brittany. Following her marriage to Louis XII in 1499, she made a number of improvements to the Castle. Symbols of ducal and royal authority, two slender spires topped the tower, dominating the horizontal line of the curtain walls. They disappeared at the end of the 17th century.

Major restoration work was carried out on the tower in the early 20th century: most of the windows were restored, the loggias reopened, most of the finely worked décor was replaced and one spire, the smaller, was rebuilt, albeit on a reduced scale.

In 2000, the Golden Crown Tower (Tour de la Couronne d'Or) entered a new phase of restoration directed by Pascal Prunet, chief architect of the Historical Monuments authority: the programme included rebuilding the spires. Their restoration is described as "stylistic", meaning the design is based on analysis of ancient documents. The aim has been to reflect and acknowledge the original 15th century construction. The finials are covered with lead overlaid with gold leaf. They are decorated with flowers, leaves and crockets and topped with a weathervane in the shape of a flame.

The presence of the two spires has re-established the balance and sense of the architectural composition as originally intended, before it was truncated by the vagaries of history. This verticality provides an emblematic signal of the Castle's presence at the heart of the modern city.

With the opening of the museum, the Golden Crown Tower (Tour de la Couronne d'Or) has regained its original purpose, joining the two main sections of the exhibitions: the main ducal residence (Grand Logis) and the Principal Governor's Palace (Grand Gouvernement).