The United Nations is celebrating World Children’s Day today with the theme of #KidsTakeOver, encouraging young people across the world to take over roles in government, media, and entertainment to raise awareness about the suffering of kids around the world.

World Children's Day has been held every year since 1954 "to promote international togetherness, awareness among children worldwide, and improve children's welfare."

The day is marked every Nov. 20 to commemorate the anniversary of the adoption of the Convention on the Rights of the Child.

This year, a group of more than 100 students and prominent young activists from around the world are “taking over” the UN headquarters to make their voices heard.

They include former child soldiers, advocates for the disabled, and those fighting for a cleaner planet. They are delivering speeches and meeting with UN Secretary General Antonio Guterres and UNICEF’s director Anthony Lake, calling for actions that will build a better world for kids.

Among the celebrities taking part in the day on social media are “Stranger Things” actor Millie Bobby Brown, “Transformers” star Isabela Moner, soccer stars David Beckham and David Villa, and cricket hero, Sachin Tendulkar.

Malala Yousafzai and Pope Francis each tweeted their support for #WorldChildrensDay, while Google created a special doodle to mark the day on their homepage.

Pop star Pink teamed up with UNICEF, the UN’s children’s charity, to release a new version of her recent hit "What About Us,” with a video that features children across the globe putting their spin on the song.

Pink said she agreed to lend the song to UNICEF “to remind the world that children and young people’s voices matter and that their perspectives must be included in the decisions that will shape their future."

Despite tremendous humanitarian progress in the decades since the first World Children’s Day, 385 million children around the world still live in extreme poverty. More than 250 million children are out of school, and 5.6 million children under the age of five died last year from preventable causes.

UNICEF says children are deeply concerned about global issues affecting both them personally, and their peers around the world. The charity released the results of a survey of children aged 9-18 in 14 countries that shows that children are worried about their peers who face poverty, terrorism, a lack of access to education.

Among the survey’s findings:

  • Children in Brazil, Nigeria, and Mexico were the most worried about violence affecting children.
  • Children in Turkey and Egypt were most likely to worry about terrorism.
  • Children in Brazil and Nigeria were most concerned about poor quality education or lack of access.
  • Children in Mexico, Brazil and Turkey were most likely to worry about unfair treatment of refugee and migrant children