Klis Fortress is a historic hilltop fortress located about 10 km northeast of Split, Croatia, perched on a steep cliff overlooking the Adriatic coast and the surrounding mountains. Dating back to ancient Illyrian times and later expanded during the Roman, Byzantine, and Ottoman periods, it served as a strategic stronghold guarding the approach to Split. The fortress is primarily outdoors, with extensive stone walls, towers, and courtyards, though there are some interior rooms, passageways, and small exhibits that can be explored. Its commanding views of Split, the surrounding countryside, and the Dalmatian coast make it a favourite destination for history buffs and photographers alike.

Entry to Klis Fortress requires a ticket, with different pricing for adults, children, and groups; combination tickets with guided tours are sometimes available. The fortress is generally open daily, with typical hours from 09:00 to 17:00–18:00 depending on the season. Guided tours may follow a schedule, and visitors should wear comfortable shoes because of steep stairs, uneven paths, and rocky terrain. There are no strict dress codes, but modest attire is recommended if exploring any chapels or religious remnants inside the fortress.

Klis Fortress can be visited year-round, though spring, early summer, and autumn are the most pleasant times due to milder weather and clearer views. Summer brings higher temperatures and more tourists, while winter can make paths slippery. Most visitors spend 1–2 hours exploring the walls, towers, and viewpoints, with additional time for taking photos and enjoying the panoramic scenery. Its proximity to Split makes it an easy half-day trip, and it has also gained modern fame as a filming location for the TV series Game of Thrones.