expedition explored the cave to making it the deepest cave in the world. For the first time in the history of speleology, the deepest cave in the world had been established outside of western Europe. Since 2001, the Krubera explorations by the Ukr.S.A. have been undertaken within the frame of the multi-year project named "The Call of the Abyss", coordinated by A. Klimchouk, Y. Kasyan, G. Samokhin and K. Markovskoy. Besides the Ukrainian speleologists, cavers from many countries such as France, Spain, Russia, Moldova, Bulgaria, United Kingdom, Ireland, Israel and Lithuania have taken part in different expeditions of the Ukr.S.A. 2001 onwards The major events in the exploration of Krubera Cave in subsequent years were as follows (see Figure 4 for spot locations): 2001 August: the Ukr.S.A. expedition led by Jurij Kasjan. Four underground camps established in the cave: in the Main Branch at −500, −1,200 and −1,400 m and in the Nekujbyshevskaja Branch at −500 m. Systematic inspection and probing of potential leads in the deep sections of the Main Branch; climbing in the Lamprechtsofen tributary; digging in the boulder choke in the Nekuybyshevskaya Branch. 2003 August: the expedition of the Kyiv Speleological Club and the CAVEX team. Tested and passed a sump at −1,440 m (now known as Sump 1), explored the post-sump section to roughly −1,660 m, continued climbing in the Lamprechtsofen tributary. 2004 July: the CAVEX team started their separate explorations, beyond the Ukr.S.A. project, in Krubera Cave. Continued exploring a section beyond Sump 1 at −1,410 m and reached the next sump (Sump 2 – "Blue Lake") at depth claimed to be −1,840 m. The depth of that point according to the subsequent Ukr.S.A. survey is −1,775 m. August: the Ukr.S.A. expedition led by Nikolay Solovyov and Alexander Klimchouk. In the Main Branch, surveyed the post-sump series, established a camp at −1,640 m, discovered a lead to a new section ("The Way to the Dream") and explored to −1,840 m. Explored the Uzhgorodskaya Series in the upper part of Krubera by climbing an 80 m high shaft in the Meander Krym. Continued working in the Nekuybyshevskaya Branch. October: the Ukr.S.A. expedition led by Jurij Kasjan. In the Main Branch, discovered a lead into a new section beyond the Big Junction at −1,790 m. Explored this section named "Windows" to a blind chamber called "Game Over" at −2,080 m. The depth mark of 2,000 m had