The Bay Area is the entire region surrounding the San Francisco Bay, including the Peninsula, East Bay, San Francisco, and North Bay, so it covers much more land area than Silicon Valley. In practice, software companies have outgrown Silicon Valley proper. Many companies are now based throughout the Bay Area.
Marathi Mumbai (the former Bombay), capital of Maharashtra state in India, port to the Arabian Sea and one of the most densely populated cities in the world. More about Mumbai. Searchable map/satellite view of Mumbai.
Tokyo is the capital of Japan. Kawasaki, Sagamihara, and Yokohama these metropolitan areas are included in administrative boundaries of Tokyo, making it most populous area of the world. So Tokyo is standing at number 1 in most populated areas of the world, containing 37,200,000 people in his lap. There is slightly decline seen in the population rate of the Tokyo according to UN, but it will still remain most populated city of the world till 2030 with its 37 million dwellers.