Windsor Castle

Windsor Castle stands as the oldest and largest occupied castle globally, serving as a working royal palace for over 1,000 monarchs across 1,000 rooms and 13 acres of grounds—surpassing Tower of London in both scale and active royal use. The State Apartments display 80 masterpieces from the Royal Collection, and St George's Chapel entombs 10 sovereigns, including Henry VIII and Charles I. Admission costs £30, making it cheaper per square foot than the average British castle ticket, while 1.5 million annual visitors enjoy year-round ceremonial events like the Changing of the Guard. Its quadrangular layout, refined over nine centuries, remains a living symbol of British monarchy unmatched in grandeur by any other fortress on this list.