The Foundations of Temples

But if a solid foundation is not found, and the site is loose earth right down, or marshy, then it is to be excavated and cleared and remade with piles of alder or of olive or charred oak, and the piles are to be driven close together by machinery, and the intervals between are to be filled with charcoal.Then the foundations are to be filled with very solid structures. The foundations being built to a level, the stylobates are to be laid.

-Vitruvius Ten Books on Architecture, Book Three Chapter Four "On the Foundations of Temples"

This is Vitruvius' description of the scene taking place 2000 years later in the images below. Because the soil is "loose earth right down" they drill hundreds of three foot diameter holes down 50-100 feet deep. They fill them with reinforced concrete, then cast the concrete footings and foundations on top. (Unfortunately, the structural engineer could not be convinced to use alder, olive or charred oak as vitruvius advises.) In most situations, the soft earth acts more like water than solid rock so the two options are to "float" the building on a wide footing, or to put down piles or caissons (as is happening below). In this case, you can imagine that the building is like an oil rig supported in a sea of soft soil on hundreds of long legs. What was that about the wise man and his choice of building sites?