Combo includes a 1-day ticket to Lotte World, where you get access to indoor Lotte World Adventure, the outdoor Magic Island, entry to the Folk Museum, and admission to the Lotte World Aquarium. PLUS admission to Seoul Sky Observatory, which offers you a 360-degree view from the top of the 123 floors at Lotte World Tower. Both Lotte and Aquarium tickets need to use on the same day, and Seoul Sky can use on the same day or on a separate day.