United States. A Rare Silver Manhattan Project Lapel Pin visually-hidden illustrating the Royal coat-of-arms of

illustrating the Royal coat-of-arms of Marie Louise

complete with four prongs on reverse

and black threaded embroidery depicting a shield in front of a factory

85mm (w) x 81

measures 19 cm (or 7 1/2 inches) in length

United States. A Rare Silver Manhattan Project Lapel Pin visually-hidden illustrating the Royal coat-of-arms ofObverse bearing the inscription MANHATTAN PROJECT A BOMB, with a castle on the bottom, reverse pin and catch with mark STERLING and WHITEHEAD & HOAG, 17. 06 mm, evidence of slight wear on obverse, extremely fine condition. Footnote: These pins were given to the workers who spent more than one year on the Manhattan Project. The Manhattan Project was the common name for what was officially known as the Manhattan Engineer District, the WWII activities