Britain's Prime Minister Boris Johnson leaves from a polling station with his dog Dilyn after casting his ballot in London Thursday. Photo: Daniel Leal-Olivas/AFP via Getty Images
Polls across the United Kingdom opened Thursday morning as millions of Brits vote in the country's third general election since 2015.
Why it matters: Prime Minister Boris Johnson has staked his leadership on a promise to "get Brexit done" by securing a majority in the election, after facing a parliamentary impasse on the issue in a minority government. But if he loses, he'll go down as one of the shortest-serving prime ministers in history.
From New Zealand to New York City, crowds have gathered to ring in the new year and the start of a new decade.
The big picture: The Pacific island nations of Tonga, Samoa, and Kiribati were the first in the world to mark the arrival of 2020, when it was still 5 a.m. on New Year's Eve on the U.S. East Coast. Here's how events have been unfolding around the U.S. and the world, in photos.
The 2010s were marked by terrorism, major natural disasters, huge political upheaval and, in the U.S. in particular, political polarization.
Zoom in: The decade began with Democratic President Obama, political gridlock in the Republican-controlled Congress and surging partisanship. It's closing with Republican President Trump impeached by the Democratic-controlled House. A bright spot has been the the U.S. economy, which has steadilyimproved since the financial crisis of the previous decade.
The House voted largely along party lines to impeach President Trump Wednesday night for abuse of power and obstruction of Congress after a daylong debate. Here's how the historic drama unfolded for Trump, Republican and Democratic lawmakers, and American voters, in photos.