The past fortnight has seen a number of anniversaries surrounding one of the most controversial episodes in human history: the development and use of the atomic bomb.
Most recently, the dates August 6 and 9 marked the consequences of these developments: the United States' dropping of atomic bombs on Hiroshima and Nagasaki in 1945.
And a week prior to these dates, August 2, was also the day that Albert Einstein signed a letter to US President Franklin D Roosevelt urging the beginning of atomic weapons research in 1939.
On this letter, Einstein would later comment: "Because of the danger that Hitler might be the first to have the bomb, I signed a letter to the President..."
"Had I known that the fear was not justified, I would not have participated in opening this Pandora's box... For my distrust of governments was not limited to Germany."
Of course, Einstein's involvement in atomic weapons remains the most complex and contentious chapter in the great man's legacy - and this is reflected in his own writings.
Among these documents, an example written by Einstein in 1952 to the scientist and author, Kenneth Heuer, reads:
"About the technical development in the field of atomic energy: I was not interested in that matter for years but rather disgusted by the course it has taken in the hands of short-sighted politicians... To me it is enough to know that the continuation of the existence of human beings is in serious doubt if no supra-national solution can be achieved." - Albert Einstein
Today, any such written reflections are naturally among Einstein's most collectible documents as the onus also falls on collectors to preserve even the darker annals of history.
Considering the singular and frank revelations contained within the letter, it's surprising that it sold for just $11,950 when auctioned at Heritage on June 22.
However, it is likely to prove a wise investment for its buyer, as future historians, institutions and buyers take an interest in its contents.
This nuclear bomb Ball Race, 160mm
In fact, Einstein autographs are among the most solid investments on the market. For evidence, you need only look at the past price histories, listed on indexes like the industry's PFC40.
According to the index, the price of a single Einstein autograph has appreciated by 242.9% over 10 years. In other words, an autograph bought for £1,750 back in 2000 could today be worth £6,000 - and perhaps even more if scribed on a historically important letter.
While such letters reflect the ideas behind the actions, World War Two was a "Total War", born of industrialisation.
And, as with any industrial system, the plans discussed by intellectuals and politicians would eventually fall into the hands of the men charged with carrying them out.
In this case, the mission fell to two crews of two so-called "Superfortress bombers": the Enola Gay and the Bockscar.
While previous WW2 bombings like London, Berlin and Dresden had been charged to thousands of planes, the Japan bombings would be carried out by these two bombers alone.
And, as with the Einstein letters, the missions of the Enola Gay and Bockscar on August 6 and 9 are also preserved. For instance, the Bockscar plan itself is on permanent display at the National Museum of the United States Air Force, Dayton, Ohio.
Elsewhere, a 160mm diameter Ball race from the construction of the 'Little Boy' bomb - originally saved as a souvenir by the scientists behind the bomb to commemorate its success - emerged on the private collectors' markets, last year, priced £15,000.
Also on the market is a black and white photograph of the Enola Gay, bearing an autograph and inscription by two of its crew: "Robert Lewis Co-Pilot 'Enola Gay' Tinian Runway Aug 6 1945" and "Thomas W. Ferebee - Bombardier - Enola - Gay - Aug 6 1945."
While these memorabilia items carry memories of one of the most horrific episodes in human history, they are essential reminders of one of the darker episodes of World War II - the likes of which will hopefully never be seen again.
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