Istanbul is one of the greatest cities in the world, at the crosroads of civilizations. It has a long history and culture, with many museums and sites to explore. Istanbul has the third oldest subway in the world. It was built in 1875 after the ones in London and in New York in 1863 and 1868, respectively. It is 573 meters long and it is located in the Beyoglu district.The Blue Mosque is the only mosque in the city with six minarets. Legend has it that when it was built, it had one minaret more than the Grand Mosque in Mecca (four was the common maximum at that time) and this was considered disrespectful in the Muslim world. In order to solve the issue, one more minaret had to be added to the Grand Mosque.Tea has become a national drink only recently. Before that it was Turkish coffee but when it became expensive and tea leaves could be grown in the Black Sea region, tea took its place. Coffee cannot be produced in Turkey because of the unfavourable climate for its production.