The shiny silver strands hanging from the branches of a Christmas tree are called tinsel. Tinsel is older than you might think—it was invented in 1610!
Tinsel was designed to mimic the way ice looks, and the earliest tinsel was made from strips of real silver (today's tinsel is PVC plastic with a metallic coating). It's a traditional Christmas decoration that is also frequently used in India for wedding celebrations and other ceremonies. You can also use the word tinsel to refer to things that look fancy but are actually worthless—which is where Hollywood's nickname, Tinseltown, comes from.