scott keyes , a 28-year-old writer , is about to travel 20,000 miles on 21 flights and visit 13 countries .
for this trip he will pay hardly anything , with all flights and hotels already covered thanks to airline miles and credit card points .
he will make stops in mexico , nicaragua , trinidad , st. lucia , grenada , germany , czech republic , ukraine , bulgaria , greece , macedonia , lithuania , and finland .
the trip took him between 10 to 15 hours to plan and cost him 136,500 frequent flyer miles .