A piece of U.S. history is for sale in New York. The Sotheby's auction house is offering late civil rights pioneer Martin Luther King's archive for $30 million, Reuters reports.

Treasures among the 7,000-item collection include a typed draft of his historic "I Have a Dream" speech, originally titled "Normalcy -- No More" and delivered 40 years ago this month at the Lincoln Memorial in Washington, D.C.

Other materials on display through September 8 include correspondence with President Richard Nixon and novelist John Steinbeck, an invitation to President John F. Kennedy's funeral and a 1948 report card from Crozer Theological Seminary -- where King received a C grade in public speaking.

The groundbreaking civil rights leader -- born in 1929 and assassinated in April 1968 -- inspired millions in the struggle for equal rights for African-Americans. "This is one of the most important non-presidential archives of the 20th century," Sotheby's vice chairman David Redden told the wire service.

King's estate is trying to sell the archive, dating from 1948 to 1968 and taken from the King family's home and the King Center in Atlanta, as a single lot. Sotheby's executives said they are looking for a buyer who will preserve the collection and exhibit the materials, the wire service reports. Sotheby's has not said why King's family is selling the archive.