Aleksei A. Navalny boarding the plane to Moscow on Sunday. He had been in Germany since August.

A police checkpoint in Kabul, Afghanistan, this month.

A team of researchers catching bats as they fly out of the Khao Chong Phran cave at dusk.

Honduran migrants on a highway in Chiquimula, Guatemala, on Saturday. The Mexican authorities have posted additional troops along the country’s southern border in anticipation of the caravan.

Philippine soldiers during a training exercise in 2019. Since November, at least two military helicopters have crashed in the Philippines.

Armin Laschet, the leader of the German state of North Rhine-Westphalia, was elected as head of the Christian Democratic Union on Saturday.

Two soldiers standing near the gate to Bobi Wine’s home in Magere, Uganda, on Friday.

Hong Kong’s Legislative Council in November. Businessmen in Hong Kong with ties to mainland China have created a new political party that some consider a Trojan horse for spreading mainland Chinese influence.

Prof. Ravi Gupta and Dr. Steven Kemp, at a University of Cambridge research institute, played a key role in identifying a more infectious coronavirus variant.

Gen. Salvador Cienfuegos was arrested in California in November and accused by American prosecutors of working for a Mexican drug cartel.

The K2 summit in August 2019. Even in more forgiving weather, climbers consider it daunting.

The national security law imposed on Hong Kong last year by the Chinese government has snuffed out many forms of dissent.

Technicians work in a Serum Institute of India factory in Pune, India, where a vaccine is being produced.

Jess Kavanagh says she always knew that her mother, Liz, was adopted. It was obvious, she said. My grandparents were white and my mam was Black.

Ron Klain, the incoming White House chief of staff, coordinated the Obama administration’s Ebola response.

Gov. Jared Polis of Colorado opening the state’s first shipment of the Covid-19 vaccine on Dec. 14.

A woman wearing a face mask is reflected in a shop window in Lisbon on Friday, as Portugal entered a new lockdown over a surge in coronavirus cases.

The entrance to the former Nazi concentration camp Buchenwald, near Weimar in Germany.

James Reichert, 14, with his parents John and Cathleen, spent increasing hours on his Xbox and on social media during the long months of lockdown and closed school.

Although cars don’t carry enough people to host a traditional superspreader event, they are small, sealed spaces that can still carry the risk of Covid-19 transmission.

A health care worker getting inoculated at a governmental hospital in Pune, India, on Saturday.

President Mahmoud Abbas of the Palestinian Authority in September. Mr. Abbas announced plans for presidential and parliamentary elections.

President-elect Joe Biden isn’t worried about deficit spending, for now.

A test launch of a hypersonic missile at the Pacific Missile Range Facility in Kauai, Hawaii, in March.

The Turcot Interchange in Montreal was empty on Saturday as the Quebec government imposed a curfew to stop the spread of the coronavirus.

The opening of the United Nations’ Human Rights Council’s main annual session in Geneva, Switzerland, last year.

Vials of Moderna’s Covid-19 vaccine in Santa Rosa, Calif., on Wednesday.

A funeral in Indonesia on Monday for someone who died from the coronavirus.

Two soldiers standing near the gate to Bobi Wine’s home in Magere, Uganda, on Friday.

A portrait of Nargis Mohammad Hasan hanging in her home in 2012. Ms. Hasan, an Iranian woman who served as an Afghan police officer, has been in prison until this past fall.

Investigators removed items from the Oslo home of Laila Anita Bertheussen and her partner, Tor Mikkel Wara, a former justice minister, in March 2019.

President Vladimir V. Putin of Russia in a videoconference on Friday, in a handout photograph released by the Kremlin.

Chancellor Angela Merkel of Germany, shown last month, has led her country for the past 15 years. She stepped down as party leader in 2018.

Prime Minister Mark Rutte of the Netherlands in The Hague on Friday.

North Korean state media released this photo of missiles at a military parade in Pyongyang, the capital, on Thursday night.

Joe Biden unveiled his spending package yesterday in Wilmington, Del.

Sales in the Bronx on November.

President-elect Joseph R. Biden Jr. unveiled a 1.9 trillion spending package aimed at combating the health and economic crises of the coronavirus pandemic.

Outside a hospital in London. The number of hospitalized Covid-19 patients in England now dwarfs the spring peak by 70 percent.

Dr. David Kessler headed the Food and Drug Administration during the presidencies of George Bush and Bill Clinton.

Australian Deputy Prime Minister Michael McCormack, center, speaks during House of Representatives Question Time at Parliament House in Canberra, in October.

Melvis Kwok, who died last month at 68, was a full-time Elvis impersonator in Hong Kong. Elvis is my savior, he once told The New York Times.

Rescuers looked for survivors of the quake in the Indonesian city of Mamuju on Friday.

The racing pigeon named Joe was found by Kevin Celli-Bird in a suburb of Melbourne, Australia.

Gen. Salvador Cienfuegos Zepeda, then defense secretary, and President Enrique Pe a Nieto of Mexico in 2016.

President-elect Joseph R. Biden Jr. presented his plans for economic relief and vaccine distribution on Thursday in Delaware.

Municipal workers removing ice from a street in Madrid on Thursday. The storm brought the heaviest snowfall the city has seen in almost 50 years.

Yemenis collecting donated food in the port of Hudaydah.

A TAP Air Portugal check-in desk at Heathrow Airport in London last month. Britain has banned travelers from Portugal and Latin America, citing concern about a new variant of the coronavirus.

Children in Knutsford, England, returning to school this month following a Christmas break.