A 16th-century synagogue has been uncovered in the city of Porto, northern Portugal, after builders tore down walls in a building in the city's historic centre.

The synagogue, built when Jews could be burned at the stake for worshipping, was hidden behind a false wall in a four-storey building on a side street in what was once Porto's Jewish quarter.

The synagogue was discovered by a Catholic priest, Father Jardim Moreira, who was in charge of turning the building into an old people's home. Fr Moreira, a keen local historian who knew the neighbourhood had been the city's Jewish quarter in the 15th century, was told by builders about the false wall. "I knew there had to be some kind of Jewish symbol behind it," he told Associated Press.