It wasn’t intended to be a royal residence
When William the Conqueror originally built Windsor Castle in the late 11th century, it was intended as a fortress. William erected the castle to oversee a strategic part of the River Thames, and to help protect Norman dominance around London. The royals of the time lived in the former palace of Edward the Confessor in the village of Old Windsor. In 1110, Henry I became the first royal to use the castle as a residence.
It’s really (really!) big
Windsor Castle is officially one of the biggest residences in the world, with around 1000 rooms and 45,000 square metres. It sits on about five hectares of land, and its imposing towers are visible from every approach.
It’s the oldest castle in the world
Or at the very least, it’s the oldest continuously occupied castle in the world. Windsor Castle has been in the royal family for almost 1000 years and 39 monarchs have graced its halls.