It's hard to believe -- and we're doing everything we can to not accept reality -- but David Letterman has officially retired. The finale of his career aired last night, May 20, closing an enormous and inimitable chapter in the late night TV history books.

We laughed and, admittedly, cried. After all, this isn't just an end of a late night TV host's run; it's the end of a friendship between one man and thousands, maybe millions, of people across the country.

It's also the end of the premier music venue on network television. Letterman went out in style, with a countdown of amazing act after amazing act, culminating in stints with Tom Waits, Eddie Vedder and Bob Dylan, and being capped off by the host's favorite band of all time, the Foo Fighters.

In 2000, after taking five weeks off the air to recover from emergency heart surgery, Letterman returned to the stage along with the Foos as they performed a song that was crucial to his recovery process: "Everlong." Now, 15 years later, Dave Grohl and company donned tuxedos and performed an extended, and ultimately explosive, rendition of the track to say fare thee well to their good friend.

Rather than the traditional performance, though, the audience and viewers weren't focused on the rockers; Letterman's crew put together the ultimate clip show honoring his career, and wrapped things up with fireworks shooting off the Ed Sullivan Theater marquee just a few blocks up from Times Square. You can see it all in the video above.

Letterman was, is and will always be untouchable in the late night TV arena. There will never be another host like him. Farewell, Dave, and thanks for the memories.

"If everything could ever feel this real forever / If anything could ever be this good again."