Lori Lightfoot addresses guests after being sworn in as mayor of Chicago during a ceremony at the Wintrust Arena on May 20th, 2019, in Chicago, Illinois.

Workers unload medicines and disposable medical supplies from a cargo plane after landing at Simon Bolivar International Airport on May 16th, 2019, in Maiquetia, Venezuela.

Two women wear face masks on May 16th, 2019, in Mexico City, Mexico.

A woman tends to her daughter, age six, who is about to receive a measles vaccine shot at a health clinic on May 15th, 2019, in Kiev, Ukraine.

Demonstrators from the pro-impeachment group By the People rally in the Cannon House Office Building Rotunda on Capitol Hill on May 14th, 2019, in Washington, D.C.

Protesters gather as New York City Mayor Bill de Blasio holds a Green New Deal rally at Trump Tower in New York City on May 13th, 2019.

A woman holds a sign during a press conference where activists delivered a computer flash drive with 10 million signatures calling for the impeachment of President Donald Trump.

A tree rests on the roof of a home that was heavily damaged by Hurricane Michael on May 9th, 2019, in Mexico Beach, Florida.

Drivers take part in a rally demanding more job security and livable incomes, at Uber and Lyft's New York City headquarters on May 8th, 2019.

To mark the one-year anniversary of the Trump administration announcing its zero-tolerance family separation policy, a life-sized cage was set up by the group Families Belong Together on Capitol Hill.

Supporters of Juan Guaidó gather to demonstrate against the government of Nicolás Maduro in a vigil on May 5th, 2019, in Caracas, Venezuela.

In celebration of Cinco de Mayo, a mariachi band performs on the floor of the New York Stock Exchange on May 3rd, 2019, in New York City.

A student standing in a tree displays a Venezuelan flag during a rally in support of opposition leader Juan Guaidó on May 2nd, 2019, in Caracas, Venezuela.

A Chilean demonstrator clashes with riot police during a May Day rally in Santiago, Chile, on May 1st, 2019.

United States Senator Chris Murphy (D-Connecticut) speaks during a news conference on health care on April 30th, 2019, on Capitol Hill in Washington, D.C.

Tens of thousands marched against the territory's proposed extradition law, which would allow the transfer of crime suspects to mainland China for trial.

Skippy Thomas, a member of the National Rifle Association, takes a selfie with President Donald Trump in the background during the NRA's annual meeting at Lucas Oil Stadium in Indianapolis, Indiana, on April 26th, 2019.

The photographer lets soil the texture of dry sand slip through his fingers at a farmer's field on April 25th, 2019, near Liebenwalde, Germany.

A couple watches as water gushes from a pipe into the former Cottbus Nord open-cast coal mine in order to create the Cottbuser Ostsee artificial lake on April 24th, 2019, near Cottbus, Germany.

Swedish environmental campaigner Greta Thunberg addresses politicians, media, and guests with the Houses of Parliament on April 23rd, 2019, in London, England.

New York City Mayor Bill de Blasio speaks about the city's response to climate change at Hunter's Point South Park on April 22nd, 2019, in the Queens borough of New York City.

Across three church and three luxury hotel bombings in Negombo, at least 207 people were killed and hundreds more injured.

The Carnival Sensation cruise ship is seen at Port Miami on April 18th, 2019, in Miami, Florida.

Two men stand at the scene of an overnight rocket attack, which no group has claimed responsibility for so far, in the Libyan capital of Tripoli on April 17th, 2019.