Yucatan
The peninsula Yucatan in the northern east corner of Mexico is a wonderful treasury with magic Maya ruins, marvelous Caribbean beaches with exciting sea-life, nice colonial towns and mystical cenotes. A cenote is a natural sinkhole, resulting from the collapse of limestone bedrock that exposes groundwater underneath. It is a huge platform of limestone with an extreme karst nature. There are no visible rivers but it has the longest known on earth in the subsurface. Consequently the cenotes are and were important for human water supply. They were holy for the Mayas and public access was forbidden.
Like the cenotes you find Maya ruins nearly everywhere. Most famous are the UNESCO world heritage sites Uxmal and Chichen Itzá. The latter one had been elected one of the seven wonder of the world few years ago.
When we entered Yucatan we had a scary experience. Later it turned out that it was less severe.