To secure him so anything happens to the president
Surrounded by water
There were so many hills/mountains around the area that made traveling hard
Isolation from other cities
The Open Door policy was written in 1899. The U.S. was interested in acquiring cheaper goods (mainly cotton) from foreign markets.
John Hays wrote this policy to protect the privileges among countries that were trading with China. He wanted countries to have equal access to ports open to trade in China, and to avoid a monopoly.
The first note in the Open Door Policy said that (1) each great power should maintain free access to a treaty port or to any other vested interest within its sphere.
