It's been a staple of holiday parties and Christmas songs for generations, and everyone knows what you're supposed to do when you're standing underneath it. But why is it a tradition to kiss underneath mistletoe? Mistletoe is unique in that it can grow even in the depths of winter, which contributes to its image of fertility and vivacity, especially when it sprouts among a batch of bare tree branches. "It's life in the midst of what seems to be death," said Bruce Forbes, a holiday expert and professor emeritus of religious studies at Morningside University in Iowa. Visit the link in bio to learn more.