2builders2tools (abbreviated to 2b2t) is the oldest anarchy server in Minecraft. An anarchy server is one where there are no rules, meaning people can use cuss words, exploit (hack), grief, bully and just be unpleasant in general. Remember this: trust NOONE except friends. If a complete stranger offers you free diamond gear, a way out of Spawn, or anything along those lines, do not accept. It will most definitely end badly.
Although 2b2t is the second oldest running server in Minecraft, behind Minecraft Online, it is one of the most popular servers because of its dedicated community of addicts. The current map has been active since December 2010, without a single reset in its entire history, and has reached over 8 terabytes in size due to the endless amount of blocks placed. The server is hosted in Sweden and was created by Hausemaster.
To enter the server you must have an installation with version 1.12, then you need to type in the IP, which is 2b2t.org. Now be warned that because of the server's popularity, there will be a queue that can be days long. To avoid this, you need to get priority from the 2b2t shop. It's $19.99 USD (£15.88 GBP) for one month, and the same amount per month for a subscription.
Most of the playerbase seems to consist of people who want to cause havoc without risk of being banned. There are a few "normal" players (FitMC being a good example).
Several "groups" have been formed over the server's 11-year-long history. Some examples are: