Before the Tomb Raider Level Editor, there was Flatland Rover.
About Flatland Online From Official Website
Press Release Flatland Takes Eidos Web Site 3D - January 19th 1999
Tomb Raider & Flatland
For 14th February 1999, Eidos, Flatland and GameSpot teamed up to sponsor a contest for Lara's birthday. The contest goal was "to build the best 3D Adventure Tomb for Lara", using the 3DML building format from Flatland and textures from the Tomb Raider games. "Flatland and Eidos were overwhelmed by the quality and scope of the entries submitted. After long hours of exploration and debate, we finally came to a decision."
On the 15th February, the winners were announced. Players could use the 3DML spot 'Winners Circle' to view the winners, or read them on the Flatland website.
GRAND PRIZE: Best Overall Spot!
Lara Goeke with 'Necropolis'
The Grand Prize Winner wins:
4 FIRST PRIZE WINNERS:
Most Beautiful Spot
Ben McClard with 'McClard's Tomb'
Matt Olsen with 'Mysteries of Osa'
Frankie Perry with 'Gargoyle's Castle'
Erik Berg with 'Akib's Castle'
First Prize Winners Win:
10 2ND PRIZE WINNERS
Second Prize Winners Win:
The tomb 'Curse of the Necropolis' was even mentioned on the Tomb Raider 3 official website, on the Community page:
There was a second contest available, which builder 'WittRaider Team' led when they created a spot called 'Lara Croft Birthday Contest Spot'. It contained puzzles that fans had to try and solve. Here is the information from the Eidos Interactive website:
On the official Tomb Raider 3 website, there was a page dedicated to Flatland, where the Rover three spots were promoted: 'Lara's Maze', 'Cave' and 'Scion Temple'.
In 2000, Eidos approached Rainer "Lemming" Kaufmann, a Flatland spot builder, and asked him to create a level for the promotion of 'Tomb Raider 3: The Lost Artefact'. This level was called 'Castle of Fate'. This is the event in his own words in 2011:
Fansite Raider Daze has taken some screenshots of the spot's gameplay. Follow this link to view them.
For completing the 'Castle of Fate', players earned themselves a new "Winner's Wallpaper" for their desktops.
The 3D environment was added to copies of 'Tomb Raider: The Lost Artefact' and also included a new set of textures - the Tomb4 blockset - that included ancient facades and surfaces.
Other known spots created were:
Lara Goeke - 'Quest for the Golden Mask'
Russ - 'Garden Maze'
Tomb Raider Texture Blocksets
These texture sets were given out on the Flatland website. Luckily, only a few of the textures wouldn't load.
In modern times, Tomb Raider Foum user UroshUchiha has managed to come across several spots and even fixed several bugs, so they are now playable. If you are interested in visiting (or revisiting) these levels, or reading about them, check out his post here.
Interestingly, Flatland is still going today, and you can download a rover that will work on modern computers.