This is a story related achievement, you will get this while playing through the main story.
*** Spoiler - click to reveal ***Complete Yay Ka-Boom-Boom mission.
Previous missions: Toreno's Last Flight, The Da Nang Thang
Next mission: Monster
Main mission progress: about 32%
Location: San Fierro
Start location: San Fierro, Doherty Garage (Red dragon logo on the map)
Reward: Access to Las Venturas and all other locations (excluding airports)
Video walkthrough: GTA Series Videos
You have to drive a car with a bomb to the yay factory and blow up the building. Be careful, if the car get heavy damage, then will blow up! Buy some weapons before start the mission. After you entered to the factory, you can hit the enemies by car. Go into the building (use the ramp), park in the red marker and active the bomb. Next kill the enemies and exit from the building before the bomb blow up. Now go to the gate, a car will come in. Kill the enemies and use the container to exit from the factory.