The 'Round the World' (Denver to Denver) record flight cover was flown by Arnold Palmer in two days during the American Bicentennial. Each envelope features a description, a map and the names of the cities visited (including Teheran, Iran) , a picture of this Learjet and the Golden Anniversary U.S. stamp commemorating 50 years of Commercial Aviation (which, further shows 2 early contract planes: a 1918 bi-plane & the Ford Stout of 1926). canceled in Denver upon departure - May 17, 1976.