The Old Town Hall, also known as Casa dos 24, was the first seat of municipal power in Porto in the 15th century, where the representatives of the 24 city guilds would gather until the end of the 17th century. Located at the foot of the Cathedral, this historic tower was the heart of medieval urban governance.

Destroyed by a fire in 1875, the building was reconstructed in 2002 based on a design by the renowned architect Fernando Távora, who used concrete, granite, and a glass facade to recreate its original volume on part of the ruins, integrating the ancient city wall and offering a large panoramic window overlooking the old city.

In 2023, the Casa became part of the Porto Museum, hosting the temporary exhibition "The Urgency of the City: Porto and 100 years of Fernando Távora," a tribute to its author and a symbol of urban identity. The building does not house permanent collections, but serves as an exhibition and symbolic space dedicated to architecture, civic memory, and urban sound, often used for sound performances and contemporary artistic activities.