A trip to the park boosts people's happiness by a similar amount as Christmas Day, according to a new study.
The more trees and vegetation at the park, the bigger the mood-boosting effect, researchers said.
Looking at flowers was one of the key things that brought joy to park visitors.
In the study visitors to parks and cities used happier words and expressed less negativity on Twitter than they did before their visit.
For three months, a team of scientists from the University of Vermont in the US studied hundreds of tweets per day that people posted from 160 parks in San Francisco.
People showed greatest happiness in large regional parks with extensive tree cover and vegetation.
