Greta Thunberg Celebrates 18th Birthday With a Hilarious Message

Greta Thunberg is celebrating her birthday. The climate change activist, who turned 18 on Sunday (January 3), celebrated her special day with a photo of herself humorously wearing a “Flat Mars Society” hoodie, mocking the Flat Earther Movement. PHOTOS: Check out the latest pics of Greta Thunberg “Thank you so much for all the well-wishes