Portland
Claude starts with the Leones, learns the shape of the city and gains access to his first contacts.
The port district is Liberty City's grimiest area and its best lesson: narrow streets, many bends and police arriving faster than expected.

A betrayal during a robbery sends Claude across all three islands and through every major organisation in Liberty City.
GTA III has the simplest story in the series, and that is a strength rather than a weakness. Claude emerges from a burning prison convoy with one aim: find the woman who shot him and left him behind.
Everything else — the Mafia, Yakuza, Cartel and a media magnate with strange jobs — is simply the route there. The game does not linger over explanations or ask anyone to like Claude.
Claude says nothing throughout the game. In 2001 that could look like an economy; in retrospect, it is clearly deliberate. A silent protagonist leaves room for the player.
Claude starts with the Leones, learns the shape of the city and gains access to his first contacts.
The port district is Liberty City's grimiest area and its best lesson: narrow streets, many bends and police arriving faster than expected.
After escaping Portland, he works with the Yakuza and enters the organised crime war.
The central island is the business district. The contacts are more influential, the jobs larger, and Claude is no longer merely an errand boy.
The final island concludes the search for Catalina and the conflict with the Colombian Cartel.
Suburbs, an airport and a power station. It has the most open space of the three areas and the toughest enemies.
The silent protagonist communicates through actions; his main drive is survival and reaching Catalina.
He does not say a single word throughout the game. The silence leaves space for the player rather than simply saving on voice work.
Claude's former partner betrays him during the opening robbery and becomes the Cartel's driving force.
The betrayal occurs in the first minute, before play begins. The rest of the story is Claude's response.
The Portland Mafia boss first offers work, then begins to see Claude as a threat.
He illustrates how Liberty City works: you are family while useful, and a problem as soon as you may become dangerous.
The explosives expert with burnt hands who helps Claude after the prison convoy escape.
He is the only character who neither demands something from Claude nor betrays him, an exception in a story full of double-crosses.
Salvatore's wife and the Yakuza leader take Claude from Portland to the second island.
Maria saves Claude and also draws him into his next problem, which is the usual pattern in this game.
The Staunton media magnate gives some of the game's strangest assignments.
Through him, the game first begins openly making fun of itself.
Claude wants to find Catalina. The game needs and explains nothing more.
It is sparse beside later entries, and that is why it works: nothing distracts from the city.
Each island is a stage with its own employers. Story progress and map progress are the same thing.
When a bridge opens, it reveals both a new area and another social layer of the city.
Claude is betrayed at the start and in turn betrays almost everyone he works for.
The game neither condemns nor excuses him. It describes the setting rather than delivering a moral lesson.
Claude achieves what he wanted and the game ends. There is no explanation or epilogue.
It was an unusually abrupt conclusion in 2001. Later entries put much more emphasis on epilogues.
Answers to the main questions about this topic
Claude is shot during a robbery and betrayed by his partner Catalina. He survives, escapes custody and works through Liberty City's three islands — via the Mafia, Yakuza and other factions — to find her.
Rockstar has never explained it. The practical effect is clear: a silent character has no stated opinions, so the player does not have to adopt someone else's personality. Later games took the opposite approach.
Claude's former partner. She betrays him in the opening scene and later leads the Colombian Cartel. She also appears in San Andreas, which takes place earlier.
Three: Portland, Staunton Island and Shoreside Vale. They open gradually as the story progresses, and each has its own employers and character.
Chronologically it is the other way round: San Andreas takes place in 1992 and GTA III in 2001, within the same universe. Catalina and several other characters appear in both.