Tibet and Beijing are most visited in China.
I am gonna go with Imperialism
Answer:
Harappa and Mohenjo-daro were thought to be the two great cities of the Indus Valley Civilization, emerging around 2600 BCE along the Indus River Valley in the Sindh and Punjab provinces of Pakistan.
European leaders responded to Islamic expansion in a very violent way. Following the initial incursions of the Islamic forces in those years, the European leaders decided it was time to take up arms and fight them in their own lands - what followed were the Crusades.