Once upon a time, there were a pair of star-crossed lovers named Dr. Meredith Grey (Ellen Pompeo) and Dr. Derek Shepherd (Patrick Dempsey). They met in a bar. He was just a guy in a bar. She was just a girl in a bar. They had sex, and then realized the next morning that he was her boss.

They started dating, and then Meredith found out that Derek was married. They broke up. She told him to pick her over his wife, and they got back together. They broke up again. They dated other people. They got back together again. Meredith almost drowned. They had a lot of make-up sex/breakup sex/all kinds of sex in on-call rooms of the hospital where they worked.

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One day, Derek told Meredith he wanted to build her a house. They moved in together. They broke up again. They got engaged! They got married with a Post-It.

They survived a shooting together. Derek got a huge promotion, and quit. They got married for real so that they could adopt a baby named Zola. They almost lost custody of the baby, but then got her back.

Meredith survived a plane crash. They decided to have a biological baby. Their son, Derek Bailey, was born during a storm in a hospital with no power.

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Derek and Meredith began fighting about their respective career paths. Derek got recruited to work for the president in D.C. He said no, and then said yes. They tried the long-distance thing. It didn't work.

Derek almost had an affair with an assistant in D.C., but then realized Meredith and their kids were everything he needed. He decided to move back to Seattle.

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On his way to settle up things in D.C., he witnessed a car accident and stopped to help the victims. He got hit by a truck and died in a hospital because of incompetent doctors.

R.I.P. Dr. Derek Shepherd.

Watch the tribute video above to relive Derek and Meredith's best moments from Grey's Anatomy. What were your favorite MerDer moments? Tell us in the comments!