Olivia Newton-John was a one-of-a-kind. The world fell in love with her as a young Australian country music singer or later, watching her in Grease with John Travolta. She continued to be relevant throughout the 70s and 80s with her music. Until recently, she had terrible luck in love, and we were all heartbroken when we heard about her breast cancer. For years after her diagnosis, she continued to perform. She would take long breaks between tours or Las Vegas residencies to focus on her health.