sentences:  During the 2007 Russian North Pole expedition, Chilingarov, accompanied by five other explorers from different countries, descended on 2 "Mir" submersibles to the seabed 13,980 feet below the North Pole in order to plant the Russian flag there and gather specimens of the seabed.In regard to the territorial claims in the Arctic, Chilingarov was quoted as saying, "The Arctic is Russian.We must prove the North Pole is an extension of the Russian landmass".