Why it looks like this

Haikou means 'mouth of the sea': the city sits where the Nandu River meets the strait separating Hainan from the mainland. Its old quarter was built largely by returning overseas Chinese traders in the early 20th century, in the qilou style — continuous arcades over the pavement, so you can walk whole streets under cover.

That matters here: Haikou is one of China's most typhoon-exposed and sun-baked cities. Beyond the arcade streets, the modern city spread along the coast after Hainan became a province and special economic zone in 1988.