Harlech Castle is a medieval fortress located in Harlech, Gwynedd, Wales. It was built by Edward I of England in the late 13th century as part of his conquest of Wales, and it is now a UNESCO World Heritage Site.

The castle sits atop a steep hill overlooking the town and the Cardigan Bay. It was designed to be both a formidable military fortress and a symbol of English power and authority. The castle's walls are made of sandstone and are over 3 meters thick at the base, with numerous towers and turrets providing a clear view of the surrounding area.

Harlech Castle played a key role in the Welsh Wars of Independence, with Owain Glyndŵr, the last native Prince of Wales, seizing the castle in 1404. During the Wars of the Roses, it was also a stronghold for the Lancastrian cause. In 1461, the Yorkists attacked the castle, which eventually fell after a long siege. Harlech Castle remained a military stronghold until the 17th century, but it eventually fell into disrepair.

Today, visitors can explore the castle's many features, including the gatehouse, the inner ward, and the great hall. There is also a visitor center that provides information on the history of the castle and the surrounding area. Harlech Castle is an iconic symbol of Welsh history and a popular destination for tourists interested in medieval architecture and military history.