What are rare earth elements and why are they important?

Rare earth elements are a group of 17 metals (15 lanthanides on periodic table, and scandium and yttrium). They are used to make magnets that turn power into motion for electric vehicles, cell phones, missile systems, and others. They have unusual fluorescent, conductive, and magnetic properties. They're also known as 'Green Elements' because they're essential to many green energy technologies.