One side of the planet was always facing the sun, with the other always facing away. This made only the strip in the middle habitable. Most native Twi'Leks lived in caves along this strip. When Ryloth was discovered, its leading export became Half-naked Twi'Lek Chicks, which was followed closely by drugs. Wat Tambor claimed Ryloth for the Confederacy of Independent Systems during the Clone Wars, but a short battle during the Outer Rim Sieges put an end to that.
Most Twi'Leks were actually from Ryloth, since very little Twi'Lek on Twi'Lek mating occurred off-world. Some of the more notable ones include: