Built as a vault attached to the Palácio da Ajuda, the museum features bullet-proof glass, five-tonne armoured doors and advanced surveillance, making it one of the most secure museums in the world.

Its star exhibit is the second-largest gold nugget ever discovered, weighing over 20kg. Extracted in Brazil during the colonial period, the nugget highlights the enduring historical and the enduring historical and economic ties between Portugal and its former colony. Other Brazilian gems on display include a raw diamond of more than 138 carats from Minas Gerais and the celebrated “Bragança Diamond”, which is actually a striking aquamarine.

The collection spans from the 16th to the 20th century, featuring jewels, decorative objects and regalia once belonging to the Portuguese Crown. Many pieces were not simply symbols of wealth but carried political significance, serving as dowries, church offerings or displays of royal power.

Security measures are far from excessive. In 2022, Portuguese jewels loaned to a Dutch exhibition were stolen and never recovered, a loss that still resonates today. The Royal Treasury Museum now ensures these priceless artefacts remain safeguarded while offering the public a rare opportunity to explore Portugal’s royal heritage and the global history that shaped it.