The Martin 187 Baltimore was a two-engined light attack bomber built by the Glenn L. Martin Company in the United States, originally ordered by the French in May 1940 as a follow-up to the earlier Martin Maryland, then in service in France. Its first flight was on 14 June 1941 and 1575 of them were built.
The geocache is placed with the permission of the regulating body of the premises, there is no need to enter the premises in any way to retrieve it. If you really struggle, dial number 3 on the complex keypad.