To come up with the list, the online travel agency asked over 1,000 travel writers, travel bloggers and travel agencies from around the world about the most beautiful cities, based on their experiences. Hanoi ranked at the top in Asia, where it is trailed by Seoul (40th), Bangkok (43rd), Jaipur in India (48th), and Beijing (50th). "With its many charming lakes peopled with locals doing Tai Chi (slow meditation in motion) and just enjoying the surroundings, a delightful blend of French and Vietnamese architecture, delicious restaurants, and an intriguing old quarter, Hanoi, although changing fast, is one of the few really beautiful Southeast Asian cities," Flight Network said.

French capital Paris took the top spot, with the authors citing its Eiffel tower and artworks in the Louvre museum. The city is also known for its cuisine and shopping, according to Flight Network. 

U.S. city New York came second on the list, followed by London in the U.K., Venice in Italy, and Vancouver in Canada.

Other cities in the top 10 were Barcelona in Spain, Cape Town in South Africa, San Francisco in the US, Sydney in Australia, and Rome in Italy.

Hanoi, which hosted the historic second summit between U.S. President Donald Trump and North Korean leader Kim Jong-un in February, received 4.7 million foreign tourists in the first nine months of this year, up 10 percent anually.

In March it was named among the top 15 destinations in the world in a poll on travel website TripAdvisor.