Skyline of the historic city of Porto at night. In the background the bridge Ponte de Arrabida. Portugal, Europe

Skyline of the historic city of Porto at sunset. In the background the bridge Ponte de Arrabida. Portugal, Europe

View towards Arrabida Bridge, Porto, Portugal, Europe

Douro River and Cityscape of Porto, elevated view, Porto, Portugal, Europe

The Dom Luis 1 Bridge over the River Douro showing Porto Metro light rail in transit and Arrabida Bridge in background, Porto (Oporto), Portugal, Europe

The Dom Luis 1 Bridge over the River Douro showing Porto Metro light rail in transit and Arrabida Bridge in background, Porto (Oporto), 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 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

Ponte da Arrabida Bridge, Porto, UNESCO World Cultural Heritage Site, Portugal, Europe

City Porto (Oporto) at Rio Douro. The old town is listed as UNESCO world heritage. In the background the bridge Ponte de Arrabida. Portugal, Europe

Bridge Ponte de Arrabida, City Porto (Oporto) at Rio Douro. The old town is listed as UNESCO world heritage. Portugal, Europe