The Tower of Arx was a massive structure situated on a small island in the middle of an ocean in the Third Era. Though the base was small in diameter, the top gracefully flared out wide enough to hold an entire town, which thrived for some time. There were four decks at the top, each wider than the one preceding it. Workers were hired in to mine cobblestone and gaurds hired to protect the burgeoning structure from griefers. There were two other small islands in the immediate vicinity of the tower; one was dedicated as a waypoint and the other was given to the Followers of Cage as payment for gaurd services. At it's height, there were around 20-40 citizens living atop the tower, with every plot of land occupied by either an individual or faction (including embassies for the Church of Cage and The Lightbringers). The tower even had its own imported animals and mushroom biome. For more images see the original reddit post. Reddit user ColdChemical submitted a post to the MinerAp subreddit on July 28th, 2012 introducing the tower. The following is the introductory paragraph from the post:
"What started as a simple little island farm has grown into a massive tower structure, composed of approximately 54 metric fucktons of cobblestone. It stretches from sea-level all the way up to the height limit. The walls are 2 blocks thick all the way up, with circular platforms dozens of chunks wide and 2 to 4 blocks thick (about 90% of these blocks were placed by yours truly; just goes to show how much one person can accomplish with a little dedication). Unlike other creations of similar size this tower is... how to say it? "Thick." There are no hollow supports, no fake support beams and 1-block-thick facades. Weeks of effort have gone into this monstrosity and it is with great pride that I unveil it publicly. I doubt I'll ever again have the time to build something so magnificent on this server again. Click this paragraph to see an awesome timeline of the tower's construction!"