One of the few organised tours from San Cristóbal was a trip to the Cañon del Sumidero in the Sumidero Ecotourism Park. About an hours drive away, in the 'city' of Chiapa de Corzo, we boarded a lancha on the Grijalva River.

We had a 2 hour boat ride on the lancha, taking us down the river through the canyon. The canyon is over 30,000 years old, and in an area of Chiapas inhabited by indigenous people for over 2,000 years. When the Spanish invaded and had the upper hand, instead of surrendering the locals jumped off the cliff. That is put into a bit more perspective when you know the canyon walls are about 200m high with the water about 40m at the deepest point.

Today, the river has a dam built on it, one of the biggest in Mexico at about 720 m high. It was built to withstand a 13 richter earthquake. A shrine to the Virgin of Guadalupe has also been built into a small recess in the wall.

The park and the river are home to thousands of birds and reptiles: herons, some type of ugly birds, green iguanas and even crocodiles. Apparently there are over 300 crocodiles in the national park and we saw three of them, and pretty big ones too. We were told they can get to 80 years old, and the longest one measured a couple of years ago was over 6m long.

After our boat ride, we had an hour to walk around Chiapa de Corzo. There wasn't too much to give it a status of 'city', it had the usual market, churches and colonial fountain in the plaza. We were able to climb the 62 steps of the spiral staircase up the church bell tower which had great views. David resisted the urge to ring the bell.

Back in San Cristóbal we had a late Menu del Dia lunch at Tierradentro, a restaurant run by Zaptista supporters. Zapatistas are indigenous people wanting to live by their own idealogies and not the State of Mexico's -It's pretty complicated so Google it, if you want to know more about the Zapatistas....