The first prototype took off in 1969 and was in service a few years later. It was an aviation marvel. It had a cruising speed of nearly twice the speed of sound. In the air, it covered one mile every three seconds.

But in over a 15 year period, only 20 of the planes were built. Two were used just for parts, and one crashed in Paris in July of 2000.

So where are the remaining 17 planes? The planes have long since been grounded, but you can still see them at airports in Paris, London, and in Manchester, England as well as in museums in New York and Washington D.C.

And this year, a whole new crop of supersonic planes may take to the skies again. These planes will be smaller, carry much fewer passengers and are not expected to enter service before 2021. What’s the cost? It hasn’t been determined yet, but don’t expect any discount fares.