String Theory : In layman's terms.
It has been an age old quest to understand, of what stuff we and all the object we see around are made . Earlier in the times of Greek philosophers like Aristotle, it was thought that we all are made up of five fundamental elements, and they even tried to understand the structure of those elements.You will we amazed to know that the geometry that we study in school which defines line , points, circle, polygon etc was actually invented by Euclid to arrive at the structure of those elements.Hence, it was his book 'Elements' from where geometry started.And in the final chapter he was able to arrive at a complex geometry involved in the structure of those elements.However, later it was understood that those were not fundamental constituent of matter, but still we kept the word element. As our know how progressed we were able to conclude that things are made of elements and these elements have more fundamental constituent called atom , which once was also thought to be indivisible.