In a world of SUVs and comically large vehicles like the Hummer. Researchers at Rice University have built the World’s smallest car, dubbed the Nanocar, it is 4 nanometers across and 3 nanometers long. The Nanocar is slightly larger than the cargo it is meant to carry.

The car is built from a single molecule. And thus the smallest you could ever build.

But why build a Nanocar? For bottom-up fabrication, of course. The Nanocar was built to transport cargo across a nanoscale surface, which has always been difficult to do gracefully. This cargo could then be used for fabrication on the nano level. For example, a fleet of Nanocars could carry the materials necessary to build a computer chip on a silicon wafer, and deposit them in the appropriate location. According to Tour, this provides a more graceful strategy for chip fabrication, and should enable more precise construction and fewer defects.

The axles really do work. And part of the research was proving it was rolling and not gliding across the surface.

At room temperature, strong electrical bonds hold the buckyball wheels tightly against the gold, but heating to about 200 degrees Celsius frees them to roll.

The next Nanocar will have an internal motor, which the team has already built, that will be powered by photons of light.