He donated his famous cowboy hat, but country singer Garth Brooks was more interested in checking out Patsy Cline's onstage costume and Ray Charles' tux on Tuesday at the Smithsonian Institution in Washington, D.C.

Brooks' trademark black Stetson Tyler cowboy hat, a stage outfit of Wrangler jeans and black cowboy boots, and a guitar he smashed on stage at a Dallas concert in 1991 will soon join the artifacts of other musical greats at the "Treasures of American History" exhibit.

"I see these things in here and all I can think of is what the hell am I doing here? It’s amazing," Brooks said.“Hopefully, time will answer that question. It always does."

Among the 10 items Brooks donated are the first gold record and cassette he received for his self-titled 1989 debut album, handwritten lyrics from the song "Beaches of Cheyenne" and the massive award plaque he received this year as the America's top-selling solo artist—having sold 123 million albums.

Brooks, 45, retired from touring in 1998 to become a stay-at-home dad. He planned to fly back home to Oklahoma on Tuesday in time to pick up one of his daughters for her Christmas recital.

He ended his nine-year touring hiatus for several benefit concerts this year, including one for a national memorial for Martin Luther King Jr. in Washington. He has upcoming concerts Jan. 25 and 26 in Los Angeles to raise money for victims of the California wildfires.

The Smithsonian initially went after Brooks' cowboy hat. But when it heard he had a gold record and recent award from the Recording Industry Association of America, Dwight B. Bowers, a curator in the museum’s division of music, sports and entertainment, said, "We were salivating." An exhibit on Brooks' career can help visitors understand the importance of country music, he said.

"The fusion of the new and the time-honored is central to the music of Garth Brooks, which blends the rhythms of rock with those of traditional country music," Bowers said.