The Pepsi Globe's roots date back to the 1940's, when the United States was in World War II. To show support of the war, Pepsi unveiled a new bottle cap that featured the Pepsi script surrounded by swirling red and blue colors on a white background. Since Pepsi was recognizable with its script logo in the same manner as its main rival Coca-Cola at the time, the cap logo was simply meant as a show of U.S. patriotism as opposed to a marketing scheme.
The cap logo, however, quickly caught on, and by the end of the war in 1945 became Pepsi's primary logo. With Pepsi gaining ground on Coke in the 1950's, the logo became so recognizable that by the time the Pepsi logo was redesigned in 1962, the swirling "red, white, & blue" bottle cap that would eventually evolve into the Pepsi Globe would remain while the script was retired in favor of a more-modern "Pepsi" typeface.
The logo was updated again in 1973, when the typeface was made smaller as to fit in the white section of the Pepsi Globe. Meanwhile, the bottle cap itself was dropped and the Pepsi Globe was "boxed in", with a red bar coming in from the left and a light-blue bar coming in from the right. A vertical variation of this would also have the red bar coming in from the bottom and the light-blue bar either coming in from the top or would be omitted altogether.
In 1991, the logo was updated again, and for the first time in the half-century existence of the Pepsi Globe, no typeface of any kind would be in the white section of the Pepsi Globe on a regular Pepsi product. Instead, the red bar would be lengthened slightly (the light-blue bar was dropped altogether) and the Pepsi script was moved on top of the Pepsi Globe and red bar.
In 1998, the red bar was dropped altogether as Pepsi adopted blue packaging (replacing white), while enlarging the Pepsi Globe and making it three-dimensional. This was the first official use of the logo as the "Pepsi Globe". The design was refined in 2003 when the typeface was updated and the Pepsi Globe became more realistic-looking. This version of the logo essentially remained the same in 2007 when Pepsi redesigned the packaging once more to show different backgrounds on each can, though the color remained blue.