Depends on what you mean by re-create. We can sometimes get the same result, but we don't necessarily know how it was done. Some types of masonry with very large close-fitting stones would be an example - for instance the ashlar masonry at Mycenae. Also at Mycenae, there are large conglomerate stones which have been sawn to make things like the door lintel of the Lion Gate. The cuts are about 2m long, and the blade was about 1mm thick - you can tell this from where the cut went a bit too far. As far as I know, it's not known how that was done.
Follow up question:
What's the deal with Damascus Steel? From what I've read, it seems to fit into OPs category of "technologies we know existed hundreds of years ago, but we still can't recreate today." Do we have any verified artifacts of Damascus Steel? Do we know what made it so special? Is it all just a bunch of retroactive hype?
Zhang Heng's seismoscope might be what you're looking for. Zhang was a prolific Chinese scholar, mathematician, engineer, and astronomer who lived during the Han dynasty. In 132, he invented an instrument for detecting earthquakes, now better known as a seismoscope. Zhang Heng's seismoscope was, as Nathan Sivin puts it, "generally considered one of the outstanding inventions of its time." However, the original seismoscope has not survived, so all that remains are a collection of historical records: A biography of Zhang from the Hou Han Shu (History of the Later Han dynasty), the Xu Han Shu by Sima Biao, the Hou Han Ji by Yuan Hong, and a biography of Emperor Shun by Fan Ye. The biography of Zhang contains the lengthiest and best known description of the seismoscope:
Outside the vessel there were eight dragon heads, each one holding a bronze ball in its mouth, while round the base there sat eight corresponding toads with their mouths open, ready to receive any ball which the dragons might drop. The toothed machinery and ingenious constructions were all hidden inside the vessel and the cover fitted down closely all round without any crevice. When an earthquake occurred the dragon mechanism of the vessel was caused to vibrate so that a ball was vomited out of a dragon-mouth and caught by the toad underneath. At the same instant a sharp sound was made which called the attention of the observers.
Now although the mechanism of one dragon was released, the seven other heads did not move, and by following the azimuthal direction, one knew the direction from which the earthquake shock had come. When this was verified by the facts there was found an almost miraculous agreement.
Nothing like this had ever been heard of before since the earliest historical records. On one occasion one of the dragons let fall a ball from its mouth though no perceptible shock could be felt. All the scholars at the capital were astonished at this strange effect occurring without any evidence of an earthquake to cause it. But several days later a messenger arrived bringing news of an earthquake in Longxi [Gansu]. Upon this every one admitted the mysterious power of the instrument. Thenceforward it became the duty of the officials of the Bureau of Astronomy and Calendar to record the directions from which earthquakes came.
Based on these records, historians have a general idea of how the device worked, but the mechanism and construction of Zhang Heng's instrument remain a mystery. Numerous attempts have been made to reconstruct the device by Western, Chinese, and Japanese historians and seismologists. I won't list all known reconstructions of the seismoscope, but I will go over some of the more of the notable ones. Several mechanisms for Zhang Heng’s seismoscope have been proposed, but most incorporate some sort of pendulum.
The earliest reconstruction was sketched by Ichisabu Fukube, the first president of the Sesimological Society of Japan, in 1875. John Milne, one of the key inventors of the first modern seismograph, designed his own reconstruction of Zhang Heng’s seismoscope in 1883. Milne was a British geologist working in Japan and the first vice president of the Seismological Society of Japan. He is credited as the first scholar to translate, popularize, and introduce Zhang Heng’s work to the West. Milne suggested that the central column of the instrument was a suspended pendulum and that the seismoscope worked based on the principle of inertia.
The architect Lu Yanzhi drew the first Chinese reconstruction in 1917, which was directly derived from Milne’s earlier reconstruction. Wang Zhenduo built an actual prototype of the seismoscope in 1936 using a suspended pendulum. The pendulum is connected to the dragon mouths on the side of the instrument. When a tremor occurs, the swinging of the pendulum presses a linking mechanism that opens one of the mouths and releases a ball. One of the problems with this model, and with Lee Shanbang's similar 1981 reconstruction, is that the pendulum often opens more than one mouth and releases multiple balls, which doesn't fit the description in the Hou Han Shu. The immobilization mechanism of Wang's reconstruction could not stop the motion caused by subsequent shock components. Wang’s goal was to adhere closely to the text, while still producing a seismoscope that functioned exactly as the text describes. He carefully researched the linguistic and technological context of each technical term as it would have been understood during the Han dynasty, a methodology that would later influence Andre Wegener Sleeswyk and Nathan Sivin’s 1981 reconstruction. Wang worked on Zhang Heng’s seismoscope for many decades, and he designed another reconstruction in 1963.
Akitsune Imamura and Takahiro Hagiwara’s reconstruction in 1937 favored an inverted pendulum for sensing earthquakes. In Imamura and Hagiwara’s model, a tremor causes the pendulum to lose its equilibrium so that a pin enters one of eight slots and pushes out a ball from the dragon's mouth. They designed their seismoscope so that only one pin enters the slot and a single ball is released after the first shock, but not for any of the subsequent shocks. An inverted pendulum was also used in reconstructions by Wang Jian in 1991 and Liang Shaojun in 1994.
Zhang Heng’s seismoscope was likely not the last of its kind. In the latter half of the 6th century, both Xindu Fang and Lin Xiaogong were said to have written a great deal about seismoscopes, which suggests that they may have constructed their own instruments possibly based on Zhang’s design. But by the Tang dynasty, the knowledge of building seismoscopes was lost. For over a century, historians have been trying to recreate the Zhang Heng's original instrument. It's a daunting task. A successful reconstruction of the device must function properly as a seismoscope, match the description in the Hou Han Shu, and it must be an instrument that someone born during the Han dynasty was capable of building. Yet without the discovery of a surviving seismoscope, a completely accurate reconstruction is still beyond our reach.
For further reading, see:
Sivin, Nathan, and Andre Wegener Sleeswyk. "Dragon and Toads: The Chinese Seismoscope of 132 AD." Chinese Science no. 6 (1983): 1-19.
Needham, Joseph, and Ling Wang. "Seismology." In Science and Civilisation in China: Mathematics and the Sciences of the Heavens and the Earth, 624-635. Vol. 3. Cambridge: Cambridge University Press, 1959.
Hsiao, Kuo-Hung, and Hong-Sen Yan. "The Review of Reconstruction Designs of Zhang Heng's Seismoscope." Journal of Japan Association for Earthquake Engineering 9, no. 4 (2009): 1-4.
For everyone suggesting Greek fire as an answer to this question, please only write an answer if you are aware of the historiographical debate about the substance and have read recent works on this topic. In particular, I'm thinking of J. Haldon's 'Greek fire revisited: recent and current research’ in Byzantine Style, Religion and Civilization: In Honour of Sir Steven Runciman (2006), as well as the view Haldon argued against, which can be found in T. Korres' Greek Fire (1995). J. Partingdon's A History of Greek Fire and Gunpowder (1999) also seems to be a relevant work, but it's not one that I've come across. There are probably more recent stuff too, as a search through a medieval bibliographical database would reveal that there are at least three articles on Greek fire published after Haldon's work.
This is important because the primary sources actually listed some of the ingredients used to create Greek fire, even if we do not know for sure its exact composition. For an answer to stand at /r/AskHistorians, it is not enough to mention this factoid on its own - why not mention the ingredients we do know about and efforts to recreate it, such as the experiments conducted by Haldon and described in his book chapter? For a good overview of this, why not check out /u/Ambarenya's answer here (though I suspect more information can still be added on the substance's historiography). If you can expand on the technical aspects of making Greek fire or supply new research, by all means post an answer, but otherwise I don't think short and simplistic statements, like the ones posted so far, are acceptable here.
Hello everyone,
In this thread, there have been a large number of incorrect, speculative, or otherwise disallowed comments, and as such, they were removed by the mod-team. Please, before you attempt answer the question, keep in mind our rules concerning in-depth and comprehensive responses. Answers that do not meet the standards we ask for will be removed.
Additionally, it is unfair to the OP to further derail this thread with off topic conversation, so if anyone has further questions or concerns, I would ask that they be directed to modmail, or a META thread. Thank you!
EDIT: To be possibly even clearer, please don't post a one-sentence answer with a link to Wikipedia.
Follow up question: My dad used to tell me that in Ancient Rome, someone had invented a new kind of glass that could bend and bounce, similar to sheets of plastic. But when the emperor found out, he destroyed the stuff and had the inventor executed for some reason. Is this true, or did he make it up to mess with me?
It is a tricky thing to say that a technology is "lost" if the real reasons that it worked in the first place were not known to the practitioners.
In the case of Roman concrete, it was known that the sand pits with darker sand near Naples and Rome worked best. We now know that these sand pits were volcanic origin and had extra silica and alumina that you would not find in a glacial deposit for example. Once these Roman sand pits were exhausted, was the technique actually lost?
In the case of Damascene steel, it is a similar story. The iron sources of the time had high naturally occurring levels of manganese and vanadium. If you teleported one of those blacksmiths into the 19th century they would tell you that the steel making process wasn't working, but not know what broke.
Is there any truth to the original question? I'm pretty skeptical that the technology for concrete was lost, as I'm assuming that the Byzantines continued to construct concrete buildings well after the fall of Rome. Was the Hagia Sofia based on Roman concrete technology?
Terra preta is an anthropogenic (man-made) soil invented in the Amazon around 500 BCE and continued to be made for some 1500 years (maybe a little over 2000 years in some places, namely along the Xingu River, bringing it up into the 1600s AD). If we could learn how to make it today it would have a huge impact on the world economy. What makes terra preta special is that, unlikely naturally occurring tropical soils, it retains its fertility for incredibly long periods of time, and under the right conditions appears to be regenerative.
This is important because one of the main factors contributing to the loss of the rainforest today is the rapid nutrient leaching that occurs in naturally-occurring rainforest soils. As old tropical farmlands became useful for little more than grazing cattle, more and more forest is cut down to provide additional farmland for a couple years before it also becomes unable to sustain crops. If we could recreate terra preta and spread the technique around the globe, long-term sustainable agricultural becomes much more viable in the tropics.
Sources:
The Antikythera Device anachronistically used gears a thousand years before their rediscovery. We now believe it was a calendar/astronomical calculator. It has been described as "the world's first computer."
See also:
While this doesn't meet the OP's original criteria, since we can certainly recreate this mechanism, I believe it is still within the spirit of the question because we have only recently had the technology to even understand what the hell the thing was in the first place.
It staggers the imagination how much human history would have changed if we had 1000 years of extra lead on this level of mechanical engineering.