In 1948, the United Nations ratified the Universal Declaration on Human Rights, proclaiming that all children have the right to a basic education. Despite this pledge, over 80 million children still do not attend primary school. Some of the most common barriers include school fees, child labor, health crises such as HIV/AIDS, discrimination and conflict. The ability to attend school is only the first challenge; quality of school is also important. In some places, there may be as many as 100-150 children in each classroom and not enough teachers or supplies.