They can eat anything, they don't get fat, their blood don't clot. The village has a special climate, but scientists don't know why these people have it all good:
https://edition.cnn.com/travel/article/limone-sul-garda-italy-elixir-wellness/index.html
https://edition.cnn.com/travel/article/limone-sul-garda-italy-elixir-wellness/index.html
