Alnwick Castle is a historic castle located in Northumberland, England. It was originally built in the 11th century and has been home to the Duke of Northumberland for over 700 years. The castle features impressive architecture, including its iconic towers and beautiful gardens. The castle is also known for its role in popular culture, having been used as a filming location for the Harry Potter films and the television series Downton Abbey. Visitors can explore its rich history, stunning interiors, and expansive grounds, making it a popular tourist destination.