The man-made
road on which
trains travel.
The earth is mounded, built up into a ridge, into which massive wooden beams--or ties--are placed at intervals of a couple feet. The two metal rails on which the train's slotted wheels ride are run perfectly parallel, and driven into the wooden beams with steel spikes the size of bananas. Ground rock, usually limestone, is spread onto the sides of the ridge and amidst the ties to combat erosion.
Get closer: railroad tracks criss-cross the countryside. On a hot July day, one can smell the black, oily sealant in the ties, the faint acrid odor of rusty old spikes that have been ripped loose and replaced. A railroad flanked by fields or forest becomes an insect freeway as wasps and dragonflies zip back and forth across the baking heat. The railroad tracks are a debris field, sometimes--little pieces of cargo come loose from the trains and fall, plastic binding strips with "Charleston, VA" stamped onto them, chunks of coal, or even hobo's rags, unidentifiable pieces of cloth and sack.
Walking along railroad tracks, I have seen the shadows of red-tailed hawks glide over me. Sometimes massive steel skeletons flank the tracks, draping electric lines overhead that sizzle and hum and buzz like cicadas. And then you look, ahead and behind you, often, for that single shining headlight that glows brightly even at midday.
That's when you get off the railroad tracks, and make way for their true masters.