No mountain system in the world has a greater influence on weather than the plateau of Tibet and its fringe, the Himalayas. Even the tallest chains in the U.S., the Rocky Mountains, Brooks Range, Cascades and Sierra Nevada, can't rival the control that the Tibetan plateau exercises over climatic conditions in Pakistan, India, China and the many smaller countries of southeastern Asia.
Megacities are the trend of the 21st century. This means metropolitan areas that are home to more than a million inhabitants. Atlanta qualifies for the label. But to see cities of truly enormous proportions, one needs to go to Asia.