There have been many inventions and traditions that have been forgotten or not practiced anymore. This will focus on Antikythera Mechanism, Baghdad Batteries, and Aeolipile. You may be thinking that batteries are around today, but you would never think of where they came from or how long ago that era was. 

The Antikthera Mechanism and this was all the way from Ancient Greece. This was an analog computer and you would never know that Ancient Greece made technology since it is not in their main history. This computer would predict eclipses, lunar phases and even the Olympics.  The next one is the Baghdad Batteries and this was a 2,000 year old artifact found in Baghdad Iraq. When filled with vinegar acid like liquid then began to generate that of a battery. This was invented during the Parthian Era and generated 1.1 volts of electricity. It was used for electroplating and mythical and religious purposes.

The last and final thing is the Aeolipile and this was invented during the 1st century AD. It is a baseless reaction steam turbine that spins when heated water is added, making steam. This was a source used for novelty or some form of amusement. It had no practical purposes for them at the time and was not useful to steam or heat food or clothes. This was one of their first attempts at technology, but it shows us that they did have the potential to make steam power.