Complex sentence: The Historic Centre of Salvador, frequently called the "Pelourinho", is renowned for its Portuguese colonial architecture with historical monuments dating from the 17th to the 19th centuries and was declared a World Heritage Site by UNESCO in 1985.
Split into simpler sentences: The Historic Centre of Salvador, frequently called the "Pelourinho", is renowned for its Portuguese colonial architecture, with historical monuments dating from the 17th to the 19th centuries. It was declared a World Heritage Site by UNESCO in 1985.