The Russian-built Tupolev Tu-144 was the world's only other supersonic airliner besides the Anglo-French Concorde. It first flew on Dec. 31, 1968, beating the Concorde into the sky by two months. During the Cold War it was a notable achievement for the then-Soviet Union.
The Tu-144 had plenty of faults -- it was difficult to handle, and noisy in the cabin during flight -- but given the limited resources and more rudimentary technology, it's impressive it worked at all.
Having been long been fascinated by this plane, getting to go inside was a big thrill for Geoff, who toured the museum for CNET. The angle was quite steep and it's hot inside, so it's quite a climb up to the cockpit.
The 144 was enough wider than the Concorde to have a three-two seating layout, accommodating up to 140 passengers (20 more than the Concorde). Most of the seats have been removed to make it easier for visitors to move around.