“The best tribute we can pay this great man is not words or in ceremonies, but actions that improve our world,” Secretary-General António Guterres told a meeting of the General Assembly on the occasion of Nelson Mandela International Day.

Observed annually on 18 July, the Day is meant to inspire people all over the world to make a positive difference in their communities by volunteering at least 67 minutes of their time in recognition of Mandela’s 67 years of public service.

“Each of us can make a difference in promoting peace, human rights, sustainable development, and lives of dignity for all,” Guterres said.

The UN chief said that he had met Mandela, also known as “Madiba”, and was struck by his wisdom, compassion, and humility.

Known as prisoner 46664 for 18 years on Robben Island, Mandela did not succumb to bitterness or personal animosity, but rose above it all to lead his country, Guterres said.

“One of the most important lessons we can learn from Nelson Mandela is that to make progress, we must look forward, however difficult that may be,” he said.

Also addressing the General Assembly, the UN body’s current president, Peter Thomson, noted that Mandela’s fight for a world that is just and fair “remains as relevant on Tuesday as it was during his lifetime.”

With conflicts raging, human rights and democratic values eroded, widening inequality and over-exploitation of the environment, “on Tuesday’s world is one in desperate need of President Mandela’s values of empathy, kindness, and respect for our common humanity.”

His values, Thomson continued, urge the international community to implement the 2030 Agenda for Sustainable Development, which envisions the world that Mandela wanted.

Delivering his keynote address, UNICEF Goodwill Ambassador Danny Glover called Mandela a “beacon of humanity triumphing over inhumanity through the force of his love for all people.”

Glover invited everyone to look to his legacy not as admirers, but rather in the spirit of “ubuntu” or humanity towards others, which Mandela embodied.

“Mandela led us on a path of justice, democracy and equity... in the process he showed the world that non-violence resistance, when combined with sustained activism, is the key to transforming a potential dead-end into a new beginning,” he said.

As part of the commemoration, the UN is on Tuesday partnering with the New York City Mayor's office on projects, including a clean-up of a public section of New York City.