President Obama calls the Grateful Dead an "iconic American band" in touching tribute

America celebrated its 239th birthday yesterday. In Chicago, another American institution reached a milestone, as the Grateful Dead turned 50 and played their penultimate show as a band. The occasion brought out many tributes. A record number of people filed into Soldier Field. New York's Empire State Building rocked Dead colors, something that has "never been done before for a rock band of this magnitude." And celebrities showed up in droves, including Katy Perry, John Mayer, Woody Harrelson, Chloe Sevigny, Liz Phair and Al Franken.

Even President Obama took note of the occasion. The Grateful Dead played a show in support of the president's first campaign in 2008, and since they were bringing their career to a close in his hometown, it was only fitting that he offered the group praise and well-wishes. "Here's to fifty years of the Grateful Dead, an iconic American band that embodies the creativity, passion, and ability to bring people together that makes American music so great," the President wrote. "Enjoy this weekend's celebration of your fans and legacy. And as [frontman] Jerry [Garcia] would say, 'Let there be songs to fill the air.' "

Read the president's letter below, and check out Billboard's review of Friday's Dead show.