Introduction to Santiago Castle (Portade Santiago): Located at the foot of St. Paul Mountain, it is a Portuguese-style building in the early 16th century and is known as the largest and strongest castle in Southeast Asia. The castle was built by the Portuguese after they occupied Malacca in 1511. In 1607, the castle was bombarded by the Dutch and only the city gate survived. The surviving ancient city gate is an ancient Western European-style building. The gate is carved with rough patterns and there is a long small arch at the top, as if wearing a hat on the head. The turret on the right is still preserved today. There is an underground tunnel inside the city gate. It is said that this underground passage leads directly to the Castle of St. John on the top of the mountain.