Dubai is the most populous city in the United Arab Emirates (UAE) and the capital of the Emirate of Dubai, the most populated of the country's seven emirates. Founded in the 1800s as a fishing village, Dubai has emerged as a major center for regional and international trade since the early 20th century and early 21st centuries with a focus on tourism and luxury. It has the second-most five-star hotels in the world and the tallest building in the world, the Burj Khalifa, which is 828 metres (2,717 ft) tall. In the eastern Arabian Peninsula, on the coast of the Persian Gulf, it is a major global transport hub for passengers and cargo. Oil revenue helped accelerate the development of the city, which was already a major mercantile hub.