What is a bouillabaise?
It is a wonderful fish stew from the south of France
More specifically it's a soup or "plate" that you would be served in Marseilles and nearby. Local fishes, like four to five anyway, firm white fleshed fish (maybe some shellfish). Garlic, tons of saffron. Typical accompaniment would be crust bread with rouille ( as in spicy, red pepper based mayonaisse).
It's possible to replicate it here if you get all of the textures right.