Over the Top is a world-record 17x17x17 Rubik's Cube. It was created by Oskar van Deventer.
Using 3-D printing technology from Shapeways, van Deventer's "Over the Top" cube took 60 hours and three attempts to make.
In late 2017, Yuxin created a mass-produced 17x17x17 with a different mechanism from Oskars, as part of their HuangLong series of big cubes.
The said world record is in question, as there is now a fully functional 22x22x22 cube. See here: (https://www.youtube.com/watch?v=lzzD1aNsLVU).