If there's one building that symbolizes the golden age of the Portuguese discoveries, it's the Mosteiros dos Jerónimos, which dominates the north side of the Praça do Império. A UNESCO World Heritage Site, the monastery and its adjacent church were built to fulfil a promise made by Portugal's king, Dom Manuel, should Vasco da Gama return safely from his inaugural voyage to India in 1498. The fact that the spices he returned with were more than enough to fund the building was, perhaps, a happy coincidence. Construction duly began in 1502 under the architect Diogo de Boitaca, who had made his name on the Igreja de Jesus in Setúbal, considered to be the first ever Manueline building.
Appropriately, Vasco da Gama's tomb now lies just inside the fantastically embellished entrance to the church. Crowned by an elaborate medley of statues, including Henry the Navigator, the 32m-high entrance was designed by the Spaniard João de Castilho, who took over the building of the church in 1517; the portal now forms the obligatory backdrop to weekend wedding photos. The church's interior is even more dazzling, displaying the maritime influences typical of Manueline architecture: the pillars are carved to resemble giant palms fanning out into a ceiling resembling a delicate jungle canopy. The church also contains the tomb of Luís de Camões (1527–1570), Portugal's greatest poet and recorder of the discoveries, alongside those of former presidents and dignitaries.
Equally impressive is the adjacent monastery, gathered round sumptuously vaulted cloisters with nautical symbols carved into the honey-coloured limestone. You can still see the twelve niches where navigators stopped for confession before their voyages of exploration, until the Hieronymite monks were forced out during the dissolution of 1834. In 2007, the monastery was again influential in blessing future trade: the Treaty of Lisbon was signed here to cement the format of the European Union.