Back when Russia was still cooperating with NASA, the two organizations developed the Kholod rocket. This beast traveled up to MACH 6.47, using scramjet technology, and it's going up for auction on September 8th.
The first Kholod flew in 1991, shortly before the USSR fell apart. The launch agency, Central Institute of Aviation Motors (CIAM) teamed up with NASA in 1998, and reached it's top speed — 4920.81 miles per hour. It holds the record of being the fastest machine to ever travel within Earth's atmosphere. Of the 9 Kholods built, the one on auction is one of only three remaining examples.
Photos via RM Auctions