The first pre-Columbian canoe ever found in a Mayan area has been discovered in a cliff-top cave in Belize. Likely dating to 200 to 800 AD, its awaiting the results of carbon testing to determine that it's the oldest found in Mesoamerica. As for what a canoe is doing halfway up a cliff in a cave - the cave appears to have been used as a burial site, and Mayan religious beliefs involve travels over water in the underworld.

The full report can be found here: Ancient Canoe Found by Wichita State University Professor on Belize Research Dig