A new detector technology lets us more than double the resolution of our electron microscope, resolving features 0.4 Angstoms apart. With a record resolution well below the shortest bond length, finding a good test object was a challenge. Twisted bilayers of two-dimensional molybdenum sulfide gave us the world's smallest ruler - where the projected distance between atoms could be made arbitrarily small.
read about it here.
The Cornell press release is here, with an update for the recognition by the Guiness Book of Records!