This old hillside Zapotec stronghold, where King Cosijoeza rebuffed the Aztecs in 1496, is north of Hwy 190 from a turnoff 11km west of Tehuantepec. A sign just past Puente Las Tejas bridge indicates ‘Guiengola 7’: the unpaved road is passable in dry weather, though the last kilometer or so (heading uphill) requires a high-clearance vehicle. The road ends at a signed trailhead, from where a sweaty 2km walk uphill through tropical woodland gets you to the remains of two pyramids, a ball court, a 64-room complex and a thick defensive wall. Many more remains lie overgrown by the surrounding forest. You’ll also see interesting limestone formations and some fine views over the isthmus. Spanish-speaking guide Victor Velázquez leads all-day trips to Guiengola for M$500, plus M$250 for a round-trip taxi. Contact him at least one day ahead: the Casa de la Cultura can help with this.