* Size: While humans have built some large structures like the Great Pyramid of Giza or skyscrapers, nothing we've created is *physically* larger than an elephant in terms of volume or weight.
* Conceptual: You could argue that things like the internet or complex scientific theories are "greater" than an elephant in terms of their impact or influence on the world.
So, there isn't a single answer. It depends on how you define "greater."