Fingertip

Rolling through the river Styx in a main battle tank is not advisable. Tanks do not float well. Unless they are floating in mercury. Though at that point you'd wonder why the river Styx was filled with anything but blood and water. Might look nice and futuristic and perhaps ominous and induce a feeling of solid liquidity leaving you slight discordant, but I'm sure there are better tricks to play than a running river of mercury. Filling the river with identical copies OF Mercury, the god, the planet or any combination of the two --like breakfast cereal with puffed wheat and toasted marshmallows, seems quite pleasing. Though it may just be that everybody gets to choose their own little version of hell and that the river and cerberus manifest on the whim of visitors. Perhaps inmates rather than visitors, but could lead to some open questions as to why you be anything but a visitor if you're driving a main battle tank.