A group of tourists inside the watch tower. Normally people can see the entire tourist area from there, but on Monday thick fog prevented visibility.
Mau Son, which used to be a favorite attraction for the French upper class and has dozens of French-built villas and old houses that are now abandoned, has become a growing tourist attraction in recent years, especially in winter.
Since February 18 a mass of cold air combined with rains has plunged northern Vietnam into its coldest spell this winter.