View across the Duoro River towards Porto's historic centre and embankment promenade, UNESCO World Heritage Site, Porto, Norte, Portugal, Europe

A view of Porto's historic centre and the Duoro River flowing towards its estuary and the Atlantic Ocean, Porto, Norte, Portugal, Europe

Nightime view across the Duoro River of Porto's south bank, Gaia, housing the cellars of famous Port wine companies, Vila Nova de Gaia, Porto, Norte, Portugal, Europe

The Dom Luis I Bridge, in augurated in 1886, UNESCO World Heritage Site, spanning the Duoro River linking the historic centre of Porto with Vila Nova de Gaia on the south bank, Porto, Norte, Portugal, Europe

View across the Duoro River towards Porto's historic centre and embankment promenade, UNESCO World Heritage Site, Porto, Norte, Portugal, Europe

View over the River Duoro in autumn, Portugal, Europe

The ancient heritage centre of Porto, UNESCO World Heritage Site, Portugal, Europe

Port wine boats, at back the Ponte de Dom Luis I Bridge, Rua Diogo Leite, Rio Duoro River, Porto, UNESCO World Cultural Heritage Site, Portugal, Europe

Cais da Ribeira with a view of the Ponte de Dom Luis I, Dom Luis I Bridge, Ribeira Quay, at back the Mosteiro da Serra do Pilar Monastery, Vila Nova de Gaia, Rio Duoro River, Porto, UNESCO World Cultural Heritage Site, Portugal, Europe

Cais da Ribeira with a view of the Ponte de Dom Luis I, Dom Luis I Bridge, Ribeira Quay, at back the Mosteiro da Serra do Pilar Monastery, Vila Nova de Gaia, Rio Duoro River, Porto, UNESCO World Cultural Heritage Site, Portugal, Europe

Cais da Ribeira with a view of the Ponte de Dom Luis I, Dom Luis I Bridge, Rio Duoro River, Ribeira Quay, Porto, UNESCO World Cultural Heritage Site, Portugal, Europe

View from district Vila Nova de Gaia to the Old Town of Porto with River Rio Duoro, at the back Ponte de Arrabida Bridge, Porto, UNESCO World Heritage Site, Portugal, Europe

View of the historic town centre of Porto with the Rio Duoro River from the Vila Nova de Gaia quarter, at back the Ponte de Arrabida Bridge, Porto, UNESCO World Cultural Heritage Site, Portugal, Europe

View to the old railway bridge Maria Pia Bridge, by Gustave Eiffel, River Rio Duoro, Porto, UNESCO World Heritage Site, Portugal, Europe

View of the historic centre of Porto with the Rio Duoro River from the Vila Nova de Gaia quarter, Porto, UNESCO World Cultural Heritage Site, Portugal, Europe

View of the historic centre of Porto with the Rio Duoro River from the Vila Nova de Gaia quarter, at back the Ponte de Arrabida Bridge, Porto, UNESCO World Cultural Heritage Site, Portugal, Europe

The historic centre of Porto with the Ribeira Quay, Rio Duoro River, Porto, UNESCO World Cultural Heritage Site, Portugal, Europe

View from Maria Pia Bridge to Porto with River Rio Duoro, at the back Porte de Luis Bridge, Porto, UNESCO World Heritage Site, Portugal, Europe

Ponte de Dom Luis I Bridge, Ribeira Quay, Rio Duoro River, Porto, UNESCO World Heritage Site, Portugal, Europe

Typical tourist boat on the Duoro River, at back the Ribeira Quay, Porto, UNESCO World Cultural Heritage Site, Portugal, Europe

Estuary of the Douro river, Porto, Portugal, Europe