The Grand Nexus
This artifact is presumed to have been destroyed when the continents split. It's location is unknown, although most dwarven records place it in the jungles near the equator on what would eventually become the Western Continent.
The building gets it name from the fact that it was placed exactly where the mystical (now debunked) ley lines that powered all spells on the planet came together from 6 different directions. It was first described by Marcia Rametope. From her journal at the time: "The building is immense and the stonework impossible for our (dwarven) people to replicate. No method I know of could possibly move those stones into position, let alone fit them so precisely. I was able to pass through the front doors made of an unusual black stone, but after a hallway that giants could have walked through, it ended in a large chamber with an immense bronze sphere radiating energy. I wanted to examine it more thoroughly, but a strange guardian prevented me from doing anything purposeful. I left in a hurry rather than die to it."
The current theory is that the building is what would eventually morph via folklore and endless retelling into the mythical Tovak Brukke. The two legends have many things in common, but the only first person account of either is on the Grand Nexus.