This Portuguese-Spanish joint issue shows two bridges over common rivers. The Alcántara bridge in Spain, over the river Tagus just a few miles before it flows into Portugal, is 61 metres tall and 194 metres long and was built by the Romans around 105 AD. Its current name comes from the Moorish time, al-qantara being the Arabic word for ‘bridge’. The Guadiana International Bridge, with a central span of 324 metres over the Guadiana river that defines the southern Portuguese-Spanish border, was opened in 1991 to link the two major settlements facing each other over the river, Vila Real de Santo António and Ayamonte. Interestingly, although the bridge has a common official name that is perfect for a joint issue, the postal administrations used the different local names.
The joint issue was designed by Atelier Acácio Santos, with photos by F. Almeida Dias, and put on sale on 14 September 2006. The Portuguese stamps were lithographed by the Mint on enamelled paper sheets of 5×5 stamps with perforation 11¾×12½. The Spanish stamps were lithographed by RCM-FNMT on paper sheets of 2×10 stamps with perforation 12¾×13¼.