Arbroath Abbey, founded in 1178 by King William the Lion, is a historic Scottish monastery with ties to Saint Thomas Becket. It's known for its association with the Declaration of Scottish Independence and its impressive red sandstone ruins. The Abbey fell into disrepair after the Reformation but has since been preserved and is open to the public. Visitors can explore the unique architecture, including the iconic Round 'O' window, and learn about the Abbey's rich history through interactive displays in the modern visitors' center.