The sale is led by a rare 4-rotor Enigma cipher machine by Heimsoeth & Rinke (estimate: £300,000-500,000). It was one of the first 4-Rotor M4 Enigmas to be manufactured by the Germans for their Navy, made between September and December of 1941. From the original “merkblatt” document inside the cover of the Enigma it is clear that this German Naval 4-rotor Enigma was issued to the 24^th U-boat flotilla, that had a base in Trondheim, Norway, to provide training to future U-boat commanders. This Enigma was captured by the Norwegian military at the end of the war and is believed to have been put into service by the Norwegian Navy for their own security operations from 1948 to 1957, during which time the world did not know the Allies had successfully deciphered M4 Enigma messages. It is completely original, in working condition, and has a unique security feature with a black metal light panel shield to prevent any bystanders from reading the deciphered messages.

Very few M4 Enigmas survived the war - M4 Enigma machines were produced in much smaller quantities than the 3-rotor machines. In addition, multiple M4 Enigmas were deployed with each U-boat and the majority of these were lost when the boats were sunk in combat or scuttled by their crews at the end of the war.The Germans were also ordered to destroy all of their Enigmas, and after the war ended Churchill instructed all remaining machines in British hands to be destroyed.

The significant role that the M4 Enigma and the secret Allied efforts to defeat its codes played in the vital Battle of the Atlantic has become increasingly well known, as historians have revisited the history of WWII with recently declassified information that is still being evaluated to this day. These factors make the German Navy M4 Enigma the ultimate historical collectible and this particular M4 is unique amongst them.

A further sale highlight are two Ichthyosaurs mounted in fighting pose (estimate: £300,000-500,000), dated to the lower Jurassic (circa 184 million years ago). These two extraordinary Ichthyosaurs were found in Holzmaden, Germany and excavated in several dozen blocks, before being pieced back into the current mount. Most Ichthyosaur specimens have been presented "flat" in their original matrix or a lighter media. To have these two preserved in three dimensions is incredibly rare and testament to the quality of the prep-work undertaken. The first complete Ichthyosaur skeleton was found at Lyme Regis in 1811 by Mary Anning.

The sale will also present a group of visually arresting sandstone formations termed gogottes (objects particularly prized by Louis XIV), a private collection of vintage NASA photographs, and fine mineral specimens and dynamically shaped meteorites, which can fit comfortably in any collection.

LONDON - Christie’s Science and Natural History online auction, which will be open for bidding until 25 October, presents a journey back in time, from the present day to the formation of the solar system 4.5 billion years ago.