Derry, also known as Londonderry, is a city on the River Foyle in Northern Ireland. It’s known for the intact 17th-century Derry’s Walls with 7 gates. Within the walls, spired St. Columb’s Cathedral displays artifacts from the 1688–9 Siege of Derry. Near the Peace Bridge, the Tower Museum has city views and historical exhibits. Huge stained-glass windows adorn the neo-Gothic red sandstone Guildhall.