Watch History Detectives online: Episode 6 NC-4: First Across the Atlantic; Howard Hughes Crash; Professor Lowe's Hot Air Balloon

A square of fabric that may have been part of an NC-4 aircraft, which was the first to fly across the Atlantic; and an altimeter that might have been part of the XF-11 aircraft flown by Howard Hughes in 1946. Also: a piece of material that may have been part of a Civil War-era hot-air balloon designed for the U.S. Army.

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