 Yvonne in Houston writes to us about an adventure she had visiting a mountain city in Oaxaca City in Mexico. We boarded a van in Potulca, Mexico, and wound our way up the Sierra Madre del Sur, going north from the Pacific coast. We were bound for Oaxaca City. The van driver made a hairpin turn every 30 seconds for almost five hours. I loved the views, gorgeous, sweeping vistas of the mountainous jungles below and plunging drop-offs that added to the already agitated state of my stomach.