IBM researchers used a new nanopatterning technique to create the "world' smallest" 3D map of the Earth. Approximately 1000 of them would fit on a single grain of salt. Separately, they also carved out a 25-nanometer tall model of the Matterhorn. A nanometer, of course, is one-billionth of a meter, so that's a 1:5 billion scale nano-mountain.
From IBM Research:
The core component of the new technique, which was developed by a team of IBM scientists, is a tiny, very sharp silicon tip measuring 500 nanometers in length and only a few nanometers at its apex..."IBM Research Creates World's Smallest 3D Map; Brings Low-Cost, Ease of Use to Creation of Nanoscale Objects"
The tip, similar to the kind used in atomic force microscopes, is attached to a bendable cantilever that controllably scans the surface of the substrate material with the accuracy of one nanometer–a millionth of a millimeter. By applying heat and force, the nano-sized tip can remove substrate material based on predefined patterns, thus operating like a "nanomilling" machine with ultra-high precision.