Colossal Cave Adventure

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Lore & Background

Colossal Cave Adventure was originally created by William Crowther in 1975 and 1976. Crowther and his ex-wife Patricia were both programmers and cavers and had extensively explored Mammoth Cave in Kentucky, the longest cave system in the world, in the early 1970s as part of the Cave Research Foundation. Crowther combined his memories and maps of the Mammoth Cave system, particularly a 1975 map of the Bedquilt area of the caves, including Colossal Cavern, with elements of the Dungeons & Dragons campaigns that he played with friends to design a game around exploring a cave for treasure. The original 1976 version of the game contains five treasures which can be collected. Although it is based on a real cave system, it contains a few fantasy elements such as a crystal bridge, magic words, and axe-wielding dwarves. The player types in one- or two-word commands to move their character through the cave system, interact with objects in the cave, pick up items to put into their inventory, and perform other actions. The program acts as a narrator, describing to the player their location in the cave and the results of certain actions. The program's replies are typically in a humorous, conversational tone, much as a Dungeon Master would use in leading players in a tabletop role-playing game.

Reader's Guide

In 1977, Don Woods expanded the game, adding ten more treasures and more fantasy elements such as a dragon and magic spells. It also adds a points system, whereby completing certain goals earns a predetermined number of points. The ultimate goal is to earn the maximum number of points—350, in the 1977 version—which involves finding all the treasures in the game and safely leaving the cave. Both versions, typically played over teleprinters connected to mainframe computers, were spread around the nascent ARPANET, the precursor to the Internet, which Crowther was involved in developing. Colossal Cave Adventure directly inspired the creation of numerous games, including Zork (1977), Adventureland (1978), Mystery House (1980), Rogue (1980), and Adventure (1980), which went on to be the foundations of the interactive fiction, adventure, roguelike, and action-adventure genres. It also influenced the creation of the MUD and computer role-playing game genres. In 2019 it was inducted into the World Video Game Hall of Fame by The Strong and the International Center for the History of Electronic Games.

Did You Know?

• The original 1976 version of the game was about 700 lines of code, plus another 700 lines of data such as descriptions for 77 rooms, navigational messages, 193 vocabulary words, and miscellaneous messages.
• Woods's 1977 version expanded the game to approximately 3,000 lines of code and 1,800 lines of data, growing to 140 map locations, 293 vocabulary words, and 53 objects.
• Crowther's then-wife Patricia was a participant in the 1972 expedition that found a connection between Mammoth Cave and the larger Flint Ridge Cave System.
• The game did not have an explicit title in it, simply stating 'WELCOME TO ADVENTURE!!' as a part of the opening message and having a file name of ADVENT.
• Woods contacted Crowther to gain access to the source code by emailing 'crowther' at every domain that existed on the ARPANET.

A Father's Cave, A Programmer's Game

William Crowther spent the early 1970s doing two things that most people never combine: programming at Bolt, Beranek and Newman, and caving with his then-wife Patricia in Mammoth Cave, Kentucky—the longest cave system on Earth. As Cave Research Foundation members, they surveyed passages and built a home teleprinter linked to BBN's PDP-1 mainframe, feeding their data into a plotting program that drove a Calcomp drum plotter to produce some of the earliest computer-drawn cave maps. Patricia even led the 1972 expedition that found a connection between Mammoth Cave and the larger Flint Ridge Cave System. After their 1975 divorce, Crowther stopped caving with the Cave Research Foundation. Driven by what he later described as an increase in spare time combined with missing his two daughters, he began working on a text-based game in Fortran on BBN's PDP-10 mainframe, interfacing through a teletype printer, that they could play. He layered his memories of the Bedquilt area and Colossal Cavern over the treasure-hunt structure of the Dungeons & Dragons campaigns he played with friends. To keep the experience welcoming for non-technical kids, he developed a natural language input system so that it would be 'a thing that gave you the illusion anyway that you'd typed in English commands and it did what you said'.

The Art of Typing English

Colossal Cave Adventure is played entirely through text. The player types one- or two-word commands—get lamp, go north, open box—and the program, acting as a narrator, describes the room they are in and the consequence of their action. Each of the dozens of locations has a name like 'Debris Room' and its own description, and the commands that work are strictly contextual: 'get lamp' only has an effect if there is a lamp present. When the parser cannot make sense of an input, it asks the player to retype their actions. The program's voice is deliberately warm and a little wry, much like a Dungeon Master guiding a tabletop session. The 1976 original offered five treasures to find, a crystal bridge, magic words, and axe-wielding dwarves who could kill you, but otherwise the game has no ending or goal beyond finding the treasures. Don Woods's 1977 revision added ten more treasures, a dragon, magic spells, and a points system in which the ultimate objective was to earn the maximum number of points—350—which involves finding all the treasures in the game and safely leaving the cave.

The Game That Named a Genre

Colossal Cave Adventure is widely recognized as the first well-known interactive fiction game and the first well-known adventure game, for which it was also the namesake. Its influence radiated outward with extraordinary speed. In 1977, Zork was born directly from its design; Adventureland followed in 1978; Mystery House and Rogue both appeared in 1980. Together those titles became the bedrock of the interactive-fiction, adventure, roguelike, and action-adventure genres, while the game's broader structural ideas also fed into the development of MUDs and computer role-playing games. Because Crowther and Woods distributed their source code freely over the nascent ARPANET, a wave of ports and modified versions spread through the late-1970s computer community. The game's reputation as one of the most influential video games ever made was formally cemented in 2019, when The Strong and the International Center for the History of Electronic Games inducted it into the World Video Game Hall of Fame.

Riding the Wires of ARPANET

In the mid-1970s, there was no gaming industry in the way we know it. Colossal Cave Adventure was played on teleprinters connected to mainframe computers, and it spread not through retail boxes or download stores but over ARPANET—the very network Crowther himself was involved in developing. That made it one of the first teletype games and one of the first pieces of software to achieve genuine viral distribution among a scattered community of researchers and hobbyists. The game's popularity in the late 1970s was, by the standards of that small world, massive. Programmers at universities and research labs around the ARPANET wrote their own ports and modified versions, often starting from Woods's 1977 source code. The experience of sitting at a teletype, typing 'go north' into a mainframe, and watching the narrator describe a dark passage in a wry, conversational tone became a shared cultural touchstone for an entire generation of early computer users.