Lunar Tower/Megacube Structure
This image is an overexposed 44x enlargement of Lunar Orbiter frame LO-III-84-M. Taken with the medium resolution camera at a distance of at least 250 miles, it shows an object dubbed by Hoagland the "Shard". The star-like object above the "Shard" is a camera registration mark.
The "Shard" has a shadow cast in the correct direction for it to be a real object on the Moon and is aligned with the local vertical rather than the grain of the film, decreasing the chance it is an emulsion abnormality.