Among them were International Olympic Committee (IOC) President Thomas Bach and International Paralympic Committee (IPC) President Andrew Parsons.

Bach was one of the first to speak during the Opening Ceremony, which was presented by four young people.

The IOC President praised the organisers for overcoming "many challenges" in his speech.

"In these uncertain times, this festival is sending a timely message of hope and confidence to the young people around the world," Bach said.

"To all the children and youngsters participating in the virtual festival - on your marks, get set and click away.

"Enjoy the many sports and activities that this incredible online programme has to offer.

"The IOC is proud to be a patron of this unique event, spreading the values of sport and the Olympic spirit in these difficult times."

The Opening Ceremony took place on United Nations (UN) World Children's Day, with the festival closing on Sunday.

The theme of the festival is "One Spirit One Heart" and young athletes around the world are set to compete in max fit, aero fit, talent contests - plus the IPC Inclusive Sports Challenge and the Special Olympics Unified Fitness Challenge.

IPC President Parsons also spoke about the difficulties of the pandemic and how it impacted social, mental and physical well-being, but left with a message of hope.

"The challenges for all of us in sport are substantial.

"Social distancing is important so we can limit the spread of COVID-19.

"However, physical activity is also important to remain healthy.

"This is why I can only applaud this initiative in providing opportunities to all you regardless of ability or social standing and to bring out the best in each and every youth participating in one of the five categories - no one will be left behind and everyone will be able to shine."

Many Paralympic athletes shared stories of accepting their disabilities too, before former UN secretary general Ban Ki-moon delivered a message in praise of unity.

Global Association of International Sports Federations (GAISF) President Raffaele Chiulli also highlighted the values of inclusivity, equality and respect in helping children participate in sport during the Opening Ceremony.

Chiulli also pointed out GAISF's role at helping to develop youth sport.

"It is an honour and pleasure to be part of the UTS World Virtual Youth Festival 2020," Chiulli said.

"What began as a simple but powerful idea in 2017 has since evolved into an intricate part of GAISF and SportAccord.

"Now, over 70 of GAISF's members are actively involved in this incredible initiative, showcasing their commitment to changing the lives of youth by harnessing the power of sport.

"During this global pandemic, GAISF has continued to work tirelessly in support of the global sports community.

"Because, as the united voice of sports, GAISF will always assist sport in its efforts to better society, build bridges and bring communities together."

Nobel Peace Prize winner Muhammad Yunus and International University Sports Federation President Oleg Matytsin also delivered speeches.

The UTS World Virtual Youth Festival 2020 Opening Conference was held afterwards, with Parsons, Chiulli and Ban among the attendees.