A simple but fiendishly hard slide puzzle of perhaps the most spectacular aircraft ever built, the SR-71 Blackbird.

This long-range, supersonic reconnaissance aircraft is capable of flying at Mach 3.2 and although now retired still is unmatched by other aircraft.

Capable of flying at over 85,000 feet and over 2,100 mph this extraordinary aircraft is featured in this puzzle.

With seven unique images and five levels of difficulty with tools to help out when you get stuck.