Date of discovery: unknown.
Location of discovery: Mars
Source photo: http://ida.wr.usgs.gov/html/m04002/m0400291.html
Now we have all heard about the tunnels on the surface of Mars and some of us have even seen them in Mars photos ourselves, but to this day, NASA has refused to talk about what they are and who made them.
The material that the tunnels are made from is translucent between the rings, but the rings themselves which act like scaffolding are smoky translucent.
I believe that an intelligent species lives below the surface of Mars and these tubes are not for transportation, but instead disposal of the methane that living organisms make. This would explain how 60% of Mars was suddenly (it happened in just days) covered in methane gas several years ago...which by the way, disappeared within a few months. SCW