Happy Valley Beijing was created in 2006.
Happy Valley Reservoir was created in 1897.
Happy Valley Shanghai was created in 2009.
Happy Valley AA was created in 1950.
Beijing Amusement Park, Chime Long Paradise, Happy Valley (Beijing)Happy Valley (Shenzhen), Honey Lake Amusement ParkHong Kong Disneyland, Nanhu, Sun Park
Happy Valley-Goose Bay was created in 1941.
A Romance of Happy Valley was created on 1919-01-26.
If it is the name then it is proper and should be capitalized Happy Valley but if you are saying, I saw a happy valley as in the valley was happy then it is common.
The Beijing Cocktail was created in 2007.
That's Beijing was created in 2001.
The Beijing Axis was created in 2002.
Beijing Hotel was created in 1915.
Beijing Marathon was created in 1981.