Bet Cuba didn’t see this coming: In his first known public appearance in four years, Fidel Castro was seen at a Havana scientific facility, a pro-government blog reported on Saturday. Photographs taken with a cell phone were posted to the blog and show the ailing 83-year-old revolutionary leader smiling and talking, with a group gathered around him. Rosa Baez, the blogger, wrote that it was a “surprise visit"—which may be an understatement. In fact, Castro has rarely appeared in photographs and videos since undergoing intestinal surgery in 2006. “He is thin, but looked good and, according to our director, is very good mentally,” reads a comment on Baez’s blog. Castro remains head of Cuba’s Communist Party. His 79-year-old brother, Raul, has been president of Cuba since 2008.