Commodities of Martian Rails: Alien Artifacts

Martian Rails, the new board game made by Mayfair Games about railroading on the Red Planet in which players build tracks and haul freight, has a long list of cool commodities that players can transport to generate revenue for their rail companies. For example:

Alien Artifacts -- Over the millennia, Mars has been visited by and temporarily housed beings from beyond our Solar System. The Face is a huge artificial construct marking their presence. Excavations occasionally discover objects from these ancient visitors.

Martian Rails is loaded with references to Martian SF!