Ershawan Fort is also named "Haimen Tiansian", Ershawan Fort is located on the top of Ershawan Mountain near the east harbor of Keelung. Following by the traditional construction method to build city gate, the front door of the platform was built by stones along the mountain, which is very splendid. Above the gate is a tablet that shows "Haimen Tiansian", which means very dangerous gate to the ocean. The strategic value of the fort explains why it was chosen to be a military base during the Ching dynasty. Visitors can view Keelung Harbor from the fort to feel its significance. The trees along the footpath around the fort make it a great choice for forest therapy. Birds and insects might greet you when you are visiting the historic site.