Final answer:
The Casablanca Conference was not attended by Stalin and therefore was not one of the meetings of the 'Big Three'; the Yalta, Tehran, and Potsdam conferences were.
Step-by-step explanation:
The Casablanca Conference was not one of the wartime meetings of the "Big Three" - Stalin, Roosevelt, and Churchill.
The other conferences, such as the Tehran Conference, the Yalta Conference, and the Potsdam Conference, were indeed attended by the leaders of the USSR, the USA, and the UK, but the Casablanca Conference, which took place in January 1943, was attended by Churchill and Roosevelt without Stalin.
These conferences were crucial in shaping the post-war world and laid the groundwork for many of the tensions that would ultimately contribute to the start of the Cold War.