Dhaka is the financial, commercial and the entertainment capital of Bangladesh, and accounts for up to 35% of Bangladesh's economy. Since its establishment as a modern capital city the population, area, social and economic diversity of Dhaka have grown tremendously. The city is now one of the most densely industrialized regions in Bangladesh. Dhaka is a major beta-global city, as it hosts the headquarters of several international corporations. By the 21st century, it emerged as a megacity. The Dhaka Stock Exchange has over 750 listed companies. The city hosts over 50 diplomatic missions and the headquarters of BIMSTEC. The city's culture is known for its rickshaws, cuisine, art festivals and religious diversity. The old city is home to around 2000 buildings from the Mughal and British periods, including notable structures such as the Bara Katra and Choto Katra caravansaries.