In this black and white photograph, Prime Minister Winston Churchill and President Franklin D. Roosevelt give a joint press conference in the Oval Office of the White House, December 23, 1941. Churchill's visit came in the aftermath of the attack on Pearl Harbor and the United States formally entering World War II earlier that month. The Prime Minister would go on to make numerous visits to Washington throughout the conflict.

This black and white photograph is of the "Big Three" - leaders of the Allied forces in World War II. Soviet Premier Joseph Stalin is on the left of the photo, with President Franklin D. Roosevelt in the center and British Prime Minister Winston Churchill on the right. The photograph was taken during the Yalta Conference in the Crimea in 1945. A number of topics were discussed by the leaders during the conference, including the post-war development of Europe and the ongoing fighting in the Pacific and possible Soviet involvement in the war against Japan.

This black and white photograph is a wider view of the well-known photo of the "Big Three" - leaders of the Allied forces in World War II - at the Tehran Conference. Soviet Premier Joseph Stalin is on the left of the photo, with President Franklin D. Roosevelt in the center and British Prime Minister Winston Churchill on the right. Members of the military from different nations, security and reporters including a film crew cover the steps, showing the chaotic scene of the actual photograph's taking.

This black and white photograph is of the "Big Three" - leaders of the Allied forces in World War II. Soviet Premier Joseph Stalin is on the left of the photo, with President Franklin D. Roosevelt in the center and British Prime Minister Winston Churchill on the right. The photograph was taken during the Tehran conference in Iran in 1943. A number of topics were discussed by the leaders during the conference, including the launch of Operation Overlord, or the Normandy Invasion, the following year.

This black and white photo is of President Franklin D. Roosevelt fishing in a stream, accompanied by British Prime Minister Winston Churchill. The presidential retreat during Roosevelt's administration was known as "Shangri-La" but was renamed by President Dwight D. Eisenhower after his grandson and is still known as "Camp David."

This black and white photograph is of President Franklin D. Roosevelt and British Prime Minister Winston Churchill in a candid moment aboard the HMS Prince of Wales during the Atlantic Conference in Placentia Bay, Newfoundland. This conference was the first formal meeting between the two men to deal with the war in Europe, and resulted in the Atlantic Charter. While the Charter was a non-binding agreement, it established a common purpose and goals for the post-war world between the two nations. The United States would finally enter the Second World War four months after the conference, following the Japanese attack on Pearl Harbor.

This black and white photograph is of the Second Quebec Conference in Quebec City, Canada in September 1944. From left to right in the photo are Alexander Cambridge, first Earl of Athlone and Governor-General of Canada, President Franklin D. Roosevelt, British Prime Minister Winston Churchill, and Canadian Prime Minister William Lyon Mackenzie King.

This black and white photograph shows President Franklin D. Roosevelt with British Prime Minister Winston Churchill seated on the West Colonnade of the White House with other gentleman standing behind them. Churchill visited the United States multiple times both during and after World War II.

In this black and white photograph, President Franklin D. Roosevelt and British Prime Minister Winston Churchill are seated outside the White House on the South Lawn. Churchill visited the United States multiple times both during and after World War II.

This black and white photograph shows President Franklin D. Roosevelt having a joint press conference with the British Prime Minister Winston Churchill in the Oval Office. This press conference took place a few weeks after the bombing of Pearl Harbor and the United States entering World War II by declaring war on Japan.

In this black and white silver gelatin photograph, President Franklin D. Roosevelt and British Prime Minister Winston Churchill attend the traditional Christmas tree lighting ceremony on December 24, 1941 on the South Grounds of the White House. Both leaders delivered defiant speeches that conveyed their joint determination to defeat the Axis powers. This trip was the first of multiple visits made by Churchill to the US both during and after World War II.

In this black and white photograph, President Franklin D. Roosevelt is seated with British Prime Minister Winston Churchill in the Rose Garden along with military Chiefs of Staff from both the United States and the United Kingdom. Those standing left to right include Field Mshl. Sir John Dill, Lt. Gen. Sir Hastings Ismay, Air Mshl. Sir Charles Portal, Gen. Sir Alan Brooke, Adm. Sir Dudley Pound, Adm. William D. Leahy, Gen. George C. Marshall, Adm. Ernest J. King, and Lt. Gen. Joseph T. McNarney. Others present at this meeting but not pictured include Brig. Gen. E. C. Jacob, Brig. Gen. John R. Deane, and presidential advisor Harry L. Hopkins.

This photograph by Harris & Ewing shows Winston Churchill and Diana Hopkins. Diana Hopkins and her father, close advisor to President Franklin D. Roosevelt, Harry Hopkins, lived at the White House from 1940 to 1943.