How did Epic Games achieve this 3D effect on their Fortnite site?

Link to Fortnites Website

Hi, everyone :) I have been looking at Epic Games' Fortnite website. And I am trying to figure out how they achieved the 3D effect on the page. It does not seem like it is a real 3D environment, but at the same time, the light setup is great! Take a look here:

Epic Games' Fortnite website - scrolled down to 3rd slide

Does any one have any idea how to do it? I would really like something similar to a project I'm working on. But All I find is Three.js, but I am quite sure that is not the solution they went with. Please help me become smarter :D