Tierradentro is the second-most important archaeological site in Colombia (after San Agustín) but gets surprisingly few visitors. Located well off the beaten track down some rough dirt roads, it is a peaceful place with friendly locals and awe-inspiring archaeological wonders. Where San Agustín is noted for its statuary, Tierradentro is remarkable for its elaborate underground tombs. So far, archaeologists have discovered about 100 of these unusual funeral temples, the only examples of their kind in the Americas. There is a fabulous walk you can do that takes in all the major tomb sites amid gorgeous mountain scenery.