Deep underground and inside the giant ice plug that sits wedged in the upper part of the Abyss of Cenote (cave) like a cork in a bottle, Professor Christoph Spötl from the Innsbruck University Quaternary Research Group and Andreas Treyer scrape the dirty layer away from the surface of the ice before drilling samples of clean ice for stable isotopes and pollen analysis. Only recently has this cave been open to scientists like Christoph to take such important samples. For many decades a lake was present in the depression at the entrance. Then in 1994 some divers hiked up the mountain to take a closer look at the lake only to find that it had disappeared! Subsequent investigation revealed a giant cave 285m deep with a large ice plug in the entrance, that for many years had prevented the wonders that lie beneath from being discovered.