surface at the North Pole. While there, her crew scattered the ashes of Arctic explorer Sir Hubert Wilkins. Calvert wrote the book Surface at the Pole about this and the other Arctic missions of USS Skate. The film Voyage to the Bottom of the Sea begins with Seaview in the Arctic for the final phase of her sea trials, including a dive under the ice cap. Two milestones in underwater exploration were achieved in 1960, the year before Voyage to the Bottom of the Sea was released. On January 23, 1960, Jacques Piccard and Lieutenant Don Walsh (USN), in the bathyscaphe Trieste, made the first descent to the bottom of the Challenger Deep. The Challenger Deep is the deepest surveyed spot in the world's oceans, and is located in the Mariana Trench, southwest of Guam. From February 16, 1960, to May 10, 1960, the submarine , under the command of Captain Edward L. Beach, Jr., made the first submerged circumnavigation of the world. Triton observed and photographed Guam extensively through her periscope during this mission, without being detected by the U.S. Navy on Guam. In the film, Seaview fires a missile from a position northwest of Guam to extinguish the "sky fire". At the time that Voyage to the Bottom of the Sea was made, the Van Allen radiation belts had only recently been discovered, and most of what the film's state concerning them is fiction. Discoveries since then clearly invalidate what the film says: the Van Allen belts (actually somewhat more radiation-dense portions of the magnetosphere) are made up of sub-atomic particles trapped by the Earth's magnetic field in the vacuum of space and cannot catch fire, as fire requires oxygen, fuel, and an ignition source, all of which are insufficient in the Van Allen Belts. Unburned hydrocarbon emissions have never reached concentrations that could support a "sky fire". At the beginning of the film, pieces of the polar ice cap are sinking, colliding with Seaview. No explanation is given as to why the ice doesn't float. The submarine Seaview The film's submarine design is unique in featuring an eight-window bow viewport that provides panoramic undersea views. In the novelization by Theodore Sturgeon, the windows are described as "oversized hull plates which happen to be transparent". They are made of "X-tempered herculite", a process developed by Nelson. In the film, Seaview has eight bow windows in the exterior shots,