Another aeronautical theme today with the Boeing 294, a prototype long range heavy bomber developed for the US armed forces and which first flew in 1937. In the event the engines it was designed for weren’t available, it was given much less powerful ones (4 * 850 hp rather than 4 * 2,600 hp) and therefore it couldn’t meet its design requirements. The single prototype was retained and used for transport purposes until being retired in 1944. It was scrapped in 1945 and the airframe was allowed to gradually bury itself in a bog where it remains.
Unusual features included wings that were so thick that a brave crew member could allegedly access the engines through a service tunnel during flight although looking at the picture it doesn’t seem feasible.