By Tobias Carroll What do you do when you’ve already won the New York City Marathon (twice), competed in the Olympics multiple times and won a silver medal at the IAFF World Half-Marathon Championship? For Germán Silva, who grew up in Veracruz, Mexico, the answer went far beyond marathons or even ultramarathons. He opted to run across the entirety of Mexico. A new article by Kevin Sieff at The Washington Post documented Silva’s genuinely epic journey. Sieff notes that the run encompassed 3,134 miles, which Silva — now 54 — estimated would take him four months to complete. (That’s a little over…