The 100th International Women's Day is being celebrated March 8 with events around the world.

To mark the anniversary, here is a look at 10 remarkable women and their impact on social trends, entertainment, business, economics and politics.

Who: Angela Merkel

What: The first woman to serve as chancellor of Germany was re-elected for her second term in 2009. A former chemist at a science academy in East Berlin, Merkel was propelled into politics through the growing democracy movement in the late 1980s. She also chaired the G8, the second woman to do so.

Angela Merkel. John MacDougall/AFP/Getty

What's next: Frequently compared to former British prime minister — and "Iron Lady" — Margaret Thatcher, Merkel was labeled the most powerful woman on the planet from 2006 to 2009 by Forbes magazine. Her ranking took a bit of a tumble last year (to No. 4). But Merkel, who oversees Europe's largest economy, remains a strong political force. Widely recognized for her political pragmatism and ability to compromise, she has emerged as a leader in the fight for fiscal stability in the face of the debt crises and growing multicultural tensions gripping European nations.

Who: Dilma Rousseff

Dilma Rousseff. Eraldo Peres/APWhat: Following the 1964 Brazilian coup that installed a military dictatorship, Rousseff took an interest in socialism and was a key founder of the Command of National Liberation (Colina) in 1967. With Colina, she promoted Marxist politics and opposition to Brazil's military dictatorship. She was jailed for two years in 1970 and became involved with the resurrection of the Brazilian Labour Party in the 1980s.

What's next: In 2010, Rousseff announced her candidacy for president for the ruling Workers' Party. As Chief of Staff for the popular Brazilian president Luiz Inácio Lula da Silva, Rousseff vowed to continue many of his policies. On Oct. 31, she won in a runoff election, becoming the country's first female president. Rousseff is now charged with overseeing Brazil's meteoric economic growth. The eyes of the world will also be on Rousseff and her country as Brazil prepares to host the 2014 FIFA World Cup and the 2016 Summer Olympics in Rio de Janeiro.

Who: Michelle Obama

Michelle Obama. John Amis/APWhat: Her husband may be president of the United States, but Michelle Obama has taken the role of First Lady and crafted it into a unique position of advocacy and support for issues ranging from school nutrition and the fight against childhood obesity, to assisting military families.

What's next: Named Forbes magazine's most powerful woman in 2010, the Harvard-educated lawyer is not afraid to get her hands dirty for causes she believes in, right down to digging up the grass outside the White House to help create a garden of healthy vegetables. When she began a campaign against childhood obesity, food retail giants promised to lower the calories in their products. Even her clothing choices — a mix of high fashion and items from mainstream retail chains — set off trends: a New York University business professor found companies register a 2.3 per cent stock gain when she wears their apparel.

Who: Lady Gaga

Lady Gaga. Axel Heimken/Pool/ReutersWhat: Singer Lady Gaga (born Stefani Joanne Angelina Germanotta) has sold 12 million copies of her debut album, The Fame (2008) and mounted a couple of sold-out tours. She will release her second album, Born This Way, on May 23. Lady Gaga currently has one of the largest Twitter followings in the world (8.6 million followers and counting), and whether you're a fan of her music or not, that kind of instant reach equals global influence.

What's next: Gaga has enjoyed a raft of hit singles and the attendant riches, but that's not the sum total of her cultural impact. Her outlandish attire and frequently bizarre performances are inspiring fashion designers and other musicians. She has also become a gay icon, using public appearances and Twitter to advocate for same-sex marriage, the repeal of the U.S. military's "Don't Ask, Don't Tell" policy, and gay emancipation in general.

Who: Queen Rania Al-Abdullah

Queen Rania Al Abdullah. Peter Kramer/APWhat: The 40-year-old Queen of Jordan is one of the most popular and influential figures in the Middle East. Dedicated to humanitarian causes, Rania's social initiatives include the Jordan River Children Program, which advocates for children's welfare, and the Madrasati ("My School") Foundation, which rebuilds and repairs poorly resourced local schools in Jordan and East Jerusalem.

What's next: Queen Rania is very active in social media, with more than a million Twitter followers and a YouTube channel where she posts monologues aimed at breaking down stereotypes about Islam. As democratic sentiment surges through the Middle East and political power changes hands, Queen Rania could play a vital role as diplomat and advocate.

Who: Arianna Huffington

Ariana Huffington. Lucas Jackson/ReutersWhat: This Greek-American journalist (born Stassinopoulos) grew to prominence in the 1990s as a conservative columnist, but changed her political stripes around the millennium, favouring leftist causes such as the environment. She ran as an independent candidate for California governor in 2003. She co-founded the news aggregator website Huffington Post in 2005; "HuffPo," as it's known colloquially, now gets close to half a billion page views a month.

What's next: On Feb. 7, AOL announced that it had acquired The Huffington Post for $315 million US, in the process installing Huffington as president and editor-in-chief of the newly formed Huffington Post Media Group, which oversees the news site as well as AOL Music, Moviefone and MapQuest. The merger solidified Huffington's claim as one of the most powerful people in modern media, and it will be interesting to see what she does with AOL's clout and resources in the coming months.

Who: Hillary Clinton

Hillary Clinton. Denis Balibouse/Pool/APWhat: The former first lady, New York senator and presidential nominee became U.S. secretary of state in 2009. In her tenure thus far, Clinton's diplomatic mettle has been tested by tensions in America's relationship with North Korea, Pakistan and China — to name just three.

What's Next: The revolutions in Egypt and Libya are forcing the U.S. to re-calibrate its Middle East policy — from building new alliances to securing oil. This means Clinton will likely be a crucial player on the world stage as Middle East nations forge new political systems and global ties. Ultimately, she could play a more important part in the course of international affairs than many of her predecessors.

Who: Oprah Winfrey

Oprah Winfrey. Gary Fabiano/Pool/GettyWhat: Since the debut of The Oprah Winfrey show in 1986, Oprah has risen swiftly to become the most influential woman in media. In the Forbes 2010 rankings, Oprah was believed to be worth $2.7 billion US, making her the richest self-made woman in America. She launched the careers of numerous other daytime TV hosts, but the "Oprah Effect" extends beyond television — her endorsement is credited with securing the 2008 Democratic presidential nomination for Barack Obama, and a recommendation in Oprah's Book Club is as good as gold.

What's next: Her TV show is drawing to a close, but with a magazine, satellite radio show and cable TV network launched in January 2011, her influence seems unlikely to wane any time soon. She has repeatedly rebuffed attempts to woo her as a candidate for public office, but as her popularity and influence grows, it's hard to believe that politics won't be in her future in some capacity.

Who: Aung San Suu Kyi

Aung San Suu Kyi. Soe Than Win/AFP/GettyWhat: Aung San Suu Kyi spent much of the past 20 years under a house arrest in Burma (also called Myanmar) enforced by the oppressive junta that currently rules the country. Burma gained its independence thanks in part to her father's leadership. Her efforts to bring democracy to her homeland have earned her a cornucopia of international awards, including the Nobel Peace Prize in 1991. She was released by Burmese authorities in November 2010, but the extent of her true freedom is still to be tested.

What's next: The last time an election was held in the country with results that were considered even vaguely legitimate by other nations, her NLD party took more than 80 per cent of the seats. Already the symbolic leader of the Burmese opposition, Suu Kyi is ideally positioned to form at least an interim government if Burma's current military regime falls.

Who: Indra Nooyi

Indra Nooyi. Stefan Wermuth/ReutersWhat: The chairperson and chief executive officer of PepsiCo joined the company in 1994 and was named president and chief financial officer in 2001. She was instrumental in the company's restructuring, pushing then-CEO Roger Enrico towards the 1997 divestment of its fast-food restaurants. She was also closely involved with the 1998 acquisition of Tropicana and the 2001 merger with Quaker Oats.

What's next: In 2006, Nooyi was named CEO of PepsiCo. Under her leadership, the company moved to acquire its two largest North American bottlers in 2009 and made its largest international acquisition in 2010, buying a majority stake in a major Russian dairy. Her decisions regarding the company's internal structure have led PepsiCo to amass the largest portfolio of brands with more than $1 billion US in annual sales: 19 in total, including Pepsi, Mountain Dew, Gatorade and Doritos. Besides the impact Nooyi's daily decisions have on national economies around the world — both those that supply the raw materials and those that buy the resulting products — the company's massive global marketing power influences an entire "Pepsi generation" of consumers.