The Piran city walls, dating back to the 7th century, represent an important part of the city's history. As the city expanded towards the harbour, new sections of walls and defensive towers were added. Today, the most extensive remains of the walls on the slope of Mogoron give Piran its distinctive appearance.
Among the seven preserved city gates, which once served as entrances through the walls, the oldest are the Muggia Gate, and the Dolphin Gate, known for its characteristic coat of arms featuring three dolphins, commissioned by the then mayor Dolfin in the 15th century.