Tehran, sometimes spelt Teheran, is the capital of Iran and Tehran Province. With a population of 8,429,807 it is also Iran's largest urban area and city, one of the largest cities in Western Asia, and is the 21st largest city in the world. Tehran is the centre of most Iranian industries including automotive, electrical, military, weaponry, textiles, sugar, cement, and chemical. It is also a leading centre for the sale of carpets and furniture. There is an oil refinery located south of the city. In the 20th century, Tehran was subject to mass-migration of people from all around Iran. The main and original inhabitants of the city are Persians and the principal language of the city is Persian with Tehranese accent spoken natively by over 98% of the city's population. 

Colombo is the largest city and former capital of Sri Lanka. It is a busy and vibrant city with a mixture of modern life and colonial buildings and ruins and a city population of 647,100. Due to its large harbour and its strategic position along the East-West sea trade routes, Colombo has a long history and was known to ancient traders 2,000 years ago.  Colombo is a huge, sprawling city, which can be visited any time of year due to its beautiful tropical climate.