For more than a century, the bridge carried road traffic on both of its decks. Today the metro crosses the upper level, while the lower level is used by cars and pedestrians crossing the river. In 1982, the bridge was designated a cultural heritage "Property of Public Interest" (Imóvel de Interesse Público) by IGESPAR, the Institute for the Management of Architectural and Archaeological Heritage, a federal agency. The bridge often is confused with the nearby Maria Pia Bridge, built nine years earlier and located half a mile to the east. Although they bear a strong resemblance, the earlier bridge only has one deck.
The most impressive way to cross the bridge is walking along the top deck. The view below is spectacular, especially at sunset. If you're in the area close to the Cathedral and planning to visit Vila Nova da Gaia, this is the best way to go. Once on the other side, there's a steep walk down the bank to the riverside where Gaia's main attractions are or alternatively, you can treat yourself to a ride on the cable car (Teleférico de Gaia).
The Alminhas da Ponte or "Shrines of the bridge" are a series of bronze memorial plates created by Portuguese sculptor José Joaquim Teixeira Lopes in 1897 to commemorate a tragedy that occurred here. Before the Dom Luís I Bridge the river crossing at this spot was made using a pontoon of around 20 old port boats lashed together by steel cables, known as the "Ponte Das Barcas". During the Peninsula Wars in 1809, Napoleon's troops invaded Porto. The panic-stricken populace rushed to the quayside and bridge in hope of escape. Alas, the Ponte Das Barcas was unable to withstand the weight of the crowds and gave way. The people were washed away and lost their lives. The river was a wilder beast in the 19th century as there were no dams upstream to temper its flow. Today the pillars of the old bridge still stand in their original position and visitors often leave candles and flowers at the shrines to pay tribute to those who lost their lives.