Health specialists once doubted India's ability to eradicate polio. The country is vast, many people live in remote, hard-to-reach areas and more than 25 million children are born each year. It was thought that a disease as tenacious as polio would find a way to survive. 

But with the help of organizations like UNICEF, the country was able to train health workers, deploy the necessary resources and make immunization a cultural norm. After years of difficult work, the country was declared polio-free on this day in 2011. 

And thanks to the country-wide coordination, India is in a far better place to confront future health crises.

Watch the video above to get a sense of how this tremendous victory unfolded.