The handover of Hong Kong's sovereignty from the United Kingdom to the People's Republic of China took place on July 1, 1997. The territory on China's Pearl River Delta became a British colony in 1842 and was occupied by Japan during World War II. After Hong Kong's return to China, the political situation was described as "one country, two systems."

Divided families, who had been split by the Hong Kong border, had hoped to be reunited after the territory's return to China. But with a daily quota of only 150 mainland Chinese allowed to settle in Hong Kong, many were left disapointed. This photo from 1999 shows mainland Chinese visitors protesting outside Hong Kong's Legal Aid Department after they were denied residency permits.

The residency issue flared up again in April 2002 when Hong Kong began deporting some 4,000 mainland Chinese who had lost legal battles to stay in the territory. These desperate families were evicted from a central park where they had been protesting.

In 2003, the highly contagious SARS virus spread through Hong Kong. The territory was hard hit by the flu-like virus and in March, the WHO declared it a pandemic. This man attended Doctor Tse Yuen-man's funeral in May. Dr. Tse had volunteered to care for SARS patients and had contracted the virus herself. Hong Kong was declared SARS-free in June 2003. Almost 300 people had died of the disease.

China's policy of "one country, two systems" has often created tension. In 2004, on the seventh anniversary of the handover, hundreds of thousands of people protested in Hong Kong, demanding political reform. They were calling for democracy and direct elections for Hong Kong's next leader.

Soaring property prices in Hong Kong forced rents higher. By 2008, it wasn't unusual to see people like Kong Siu-kau living in so-called "cage homes," 15-square-foot (1.4 square meters) wire mesh cubicles, eight of which were usually crammed into one room. Today an estimated 200,000 people call a wire cage, or a single bed in a shared apartment, home.

On the twentieth anniversary of the government's brutal crackdown in Tiananmen Square, Hong Kong residents gathered for a candlelight vigil in Victoria Park. It showed how different Hong Kong is from China, where the massacre of pro-democracy supporters and students on June 4, 1989, is usually only referred to as the June Fourth Incident.

Starting in September 2014, large-scale protests demanding more autonomy rocked Hong Kong for over two months. Beijing had announced that China would decide on the candidates for the 2017 election of Hong Kong's chief executive. The protests were referred to as the Umbrella Revolution, because protesters used umbrellas to fend off pepper spray and tear gas used by police.

Less than a year after the Occupy Central protests ended, China played against Hong Kong in a soccer World Cup qualifiying match on November 17, 2015. The guests did not receive a friendly welcome in Hong Kong. Fans booed when the Chinese national anthem was played and held up posters saying "Hong Kong is not China." The match ended 0-0.

In February 2016, Hong Kong's rough police tactics made headlines again. Authorities tried to remove illegal street vendors from a working-class Hong Kong neighborhood. They sent riot police, who used batons and pepper spray against protesters, and also fired live warning shots into the air. The street clashes were the worst since the Umbrella Revolution in 2014.

Malala Yousafzai, a 17-year-old activist from Pakistan, is the youngest ever person to be awarded the Nobel Peace Prize. Two years ago, Malala was shot by the Taliban for her work promoting education for girls. Receiving her prize, Malala said the life story she told was not unique but "the story of many girls." She dedicated the award to the "forgotten children who want education."

Twenty-three-year-old German student Tugce Albayrak was fatally attacked in November, after she intervened on behalf of two girls who were being harassed by three men at a fast food restaurant. Her death ignited a debate on civic courage, with many Germans asking whether people today are as courageous as they should be in such circumstances.

Joshua Wong (center) is the 18-year-old leader of the student protest movement which has been fighting for democracy in Hong Kong. Along with the activist group Occupy Central, the students occupied areas of the financial and governmental districts in the city, calling for the right to vote freely for the leadership of the semi-autonomous state without interference from mainland China.

After being abused and beaten by her employers while working as a maid in Hong Kong, Erwiana Sulistyaningsih has become an advocate for better laws to protect others who could find themselves in her situation. The 23-year-old Indonesian's courage to talk about her ordeal meant that her case sparked international outrage, and has shed light on the plight of migrant workers around the world.

Since 43 students went missing in Mexico in September, only one of their bodies has been identified - that of 19-year-old Alexander Mora, who was studying to be a sports teacher. The students' disappearance highlighted a huge problem in the country - at least 26,000 have gone missing in the past seven years. Thousands of Mexicans continue to protest, calling for answers and justice.

Lina Ben Mhenni, a Tunisian blogger, has continued to work for democracy in her country since the Tunisian Revolution, which marked the start of the Arab Spring. The 31-year-old activist writes in Arabic, French and English on her blog "A Tunisian Girl," speaking out against corruption and censorship. Mhenni's work gives a female voice to democracy in the Middle East and North Africa.