The capital of the Red River Delta is Hanoi, a five-letter word. Hanoi is the capital of Vietnam and is located in the northern part of the country. It is one of the oldest cities in Southeast Asia and has a long history of being an important cultural and political center. The city is known for its many lakes, temples, and pagodas, as well as its vibrant street life. Hanoi is also home to a number of universities and other educational institutions.