TIME takes a look at how people across the Northern Hemisphere are getting ready to greet the long, hot days ahead.
Happy First Day of Summer
Mark Lennihan / AP
Tatjana Eres of Denmark holds up her son, ten-month-old Leo Erichsen, during a mass-yoga class in New York City's Times Square. Thousands of yoga enthusiasts came to mark the summer solstice -- the official beginning of summer -- on Wednesday, June 20, 2012.
