Aqueduto da Usseira (Usseira Aqueduct), Obidos (must see)

The Usseira Aqueduct, a marvel from the 16th century commissioned by Queen D. Catarina of Austria, stands as a testament to architectural ingenuity and water engineering. Funded in exchange for the Várzea do Mocharro, renamed Várzea da Rainha, this aqueduct served as a vital water supply for Óbidos, Portugal. Stretching approximately 6 km, it unfolds in three sections, encompassing 3 km of subterranean conduits from Usseira to Vale dos Arcos, 2.5 km of elevated arcades over the valley to the gate of Nossa Senhora da Piedade on Óbidos' walls, and around 500 m of underground channels from Rua Direita to Chafariz da Praça.

This single-story arcade aqueduct, robustly built in stone with masonry covering near the town, features narrow round arches and slightly pointed or broken wider arches. The architects/builders remain uncertain, with speculations involving the possibility of Afonso Álvares overseeing its execution through master masons Gonçalo de Torralva or Onofre de Carvalho. Alternatively, the layout could be credited to masters like Gonçalo de Torralva, António, Álvaro, and Francisco Fernandes, who were active in Óbidos during the late 16th century.

Beyond its structural prowess, the Usseira Aqueduct served three fountains-Mãe-de-Água (now destroyed), Praça, and Bica-along with several drinking fountains, leaving an indelible mark on Óbidos' historical landscape.