Republican presidential candidate Ted Cruz carries his daughter Caroline as he arrives at a campaign event in Jefferson, Iowa, on Feb. 1.
On Monday night, thousands of Iowans will gather in community centers, fire stations, libraries and town halls to have the nation's first say in who the Republican and Democratic presidential nominees should be.
Republican presidential candidate Jeb Bush shakes hands with a supporter in Des Moines on Feb. 1.
Republican presidential candidate Donald Trump listens as his daughter Ivanka speaks at a campaign rally in Waterloo, Iowa, on Feb.1.
Democratic presidential candidate Bernie Sanders greets a supporter while visiting his campaign's Iowa headquarters in Des Moines on Feb. 1.
Democratic presidential candidate Hillary Clinton takes photos with workers at her campaign office in Des Moines on Feb. 1.
Supporters of Democratic presidential candidate Martin O'Malley campaign on a busy street corner in Des Moines on Feb. 1.
Supporters of Republican presidential candidate Rand Paul campaign during morning rush hour in Des Moines on Feb. 1.
Supporters react as Democratic presidential candidate Sen. Bernie Sanders (I-Vt.) arrives at a campaign event at Iowa State University in Ames on Jan. 31.
A Trump supporter holds his child aloft for Republican presidential candidate Donald Trump to see as other supporters clamor for autographs at a rally at the Gerald W. Kirn Middle School in Council Bluffs, Iowa on Jan. 31.
The head of an Uncle Sam eagle sits on a bar stool at the Marriott hotel bar in Des Moines on Jan. 31.
Kelsey Johnson of Greensburg and friends cheer as Democratic presidential candidate Sen. Bernie Sanders speaks at a rally at Grand View University in Des Moines on Jan. 31
Republican presidential candidate Donald Trump is mobbed by supporters after a rally in Council Bluffs on Jan. 31.
Democratic presidential candidate Hillary Clinton shakes hands with supporters afters speaking at a rally in Sioux City, Iowa, Jan. 31.
A supporter holds up a giant poster of Republican presidential candidate New Jersey Gov. Chris Christie at a pub in West Des Moines on Jan. 31.
Republican presidential candidate Ben Carson poses for a picture with an audience member following an event at Fireside Pub and Steak House in Manchester, Iowa, on Jan. 31.
Sen. Bernie Sanders poses for a selfie with a supporter during a rally in Waterloo, Iowa on Jan. 31.
Republican presidential candidate Jeb Bush, left, and U.S. Senator Chuck Grassley (R-Iowa) laugh during a Busn event at the Cedar Falls Eagles Club on Jan 30.
Alex Richmond, who traveled from his home state of Michigan, works in front of his laptop on a phone list for Republican presidential candidate Marco Rubio at the campaign's headquarters in Akeny, Iowa, on Jan. 30.
Supporters look on as Hillary Clinton speaks during a "get out to caucus" event at Washington High School in Cedar Rapids, Iowa, on Jan. 30
Candace Richarel cheers as Sen. Bernie Sanders speaks at a rally in Cedar Rapids on Jan. 30.
Florida Senator and Republican presidential hopeful Marco Rubio speaks at PZAZZ! Event Center in Burlington, Iowa, on Jan. 29.
Heidi Cruz whispers to husband and Republican presidential candidate Sen. Ted Cruz as they are introduced during an event in Ringsted, Iowa on Jan. 29.
Sen. Ted Cruz casts a shadow on an Iowa flag at an event at Bridge View Center in Ottumwa, Iowa, on Jan. 26.
An American flag is painted on the side of a barn outside Webster City, Iowa on Jan. 22.
Gallery: Sunday in Pictures