Atlas Obscura
Major Adams Monument in Johannesburg, California
The X-15 rocket plane program is barely remembered today, but it was the first venture by crewed craft to the edge of space. The rocket plane, carrying a human pilot, would be carried to high altitude under the wing of a modified B-52. The plane would then be released, and the pilot would initiate a flight plan, firing the rocket engine and commonly flying up to the edge of space. A number of t…