The b1.8 Menu Panorama

Project Summary

Everyone should be familiar with this world. It's the one that always appeared on Minecraft's main-menu (title-screen), blurred and slowly rotating around. It first appeared in 2011 for Minecraft Beta 1.8 and stayed for many years, until it was only recently replaced in 1.13 and every version after that. And nobody ever knew the seed... until now!

The seed was found on 18th of July 2020 at around 5:45 AM UTC.

Version: Beta 1.7.3
Coordinates: X=61.48~, Y=75, Z=-68.73~
Seed: 2151901553968352745 OR 8091867987493326313 (both work)

Why 2 seeds? There are actually 2^16 (=65536) seeds that will all generate this identical world. This is because these older versions of Minecraft used only 48 of the bits of the seed. Here's the formula for getting all of them, as explained by Earthcomputer:
25357015387625 + 2^48k, 0 <= k < 2^16; (k is an integer)
But only the 2 seeds mentioned are "valid", in the sense that they can be naturally generated by Minecraft (because of Java's random function implementation). Also note, that there is not any word/string of characters that will produce this seed, it was generated randomly. And no, this has nothing to do with "shadow seeds", those aren't in these versions. There are no differences between these seeds. What can change however is placement of trees and such, because that also depends of the order chunks are generated.

Here's a brief summary of what happened:
The research itself took about a month. It started on 14th June 2020, when Tomlacko researched as much as he could about the panorama and it's world (the version, world axis and the exact Z coordinate using clouds) and shared my findings on SalC1's Discord server, where a similar project was currently taking place (finding the seed of the pack.png image). Then, a part of a new Minecraft-research-oriented Discord server Minecraft@Home was dedicated to this project and work quickly started to be done. It would never have been possible without them.

Minecraft@Home is a volunteer distributed computing project powered by BOINC allowing users to volunteer their idle computers to help advance Minecraft-related research, one of which was this panorama project. In less than 24 hours after launching the panorama application; a volunteer host on Minecraft@Home found this seed. This was approximately 93 days of processing time at a total of 54.5 exaFLOPs compressed into 24 hours. Another ongoing project is search for the tallest cactus (currently we have found a 22 block high one!).

Here's CREDITS to the core group of people who made this happen (and the main thing they did), in reverse-chronological order:

Earthcomputer, Cortex, Neil - wrote the biome and terrain checking code and found the seed
DutChen18 - made multiple tools/mods to help with the recreation and gathering data for the seed checking
MC PseudoGravity - reversed the tallgrass colors and found the biome values in the panorama
Philipp_DE - hosted the recreation MC server and screenshotting bot
Tomlacko - started the project, found the coordinates, made panorama viewer with recreation overlay

...and many other people who helped in other ways (such as building the recreation block-by-block) listed here: https://mcatho.me/panoramacredits