Trickeye Museum is a playful optical-illusion museum in Hongdae, built around painted scenes and 3D installations that visitors step into for photos. It is unabashedly light entertainment rather than a serious art stop.
Come with the right expectations and it can be fun, especially with children or friends who enjoy staged photos. If you are short on time in Seoul, Hongdae's streets, cafes, and live music are the stronger draw.