About 25,000 of world's top AIDS researchers, political leaders, diplomats and other stakeholders are gathering in Washington for Sunday's International AIDS Conference.

The biennial conference will take place through July 27 in the U.S. capital, a city faced with one of the nation's highest rates of HIV infections. The HIV virus usually leads to AIDS .

Secretary of State Hillary Clinton, former President Bill Clinton and former first lady Laura Bush will speak at the conference. Other high-level speakers include World Bank President Jim Yong Kim, and Microsoft chairman and philanthropist Bill Gates.

AIDS is a disease that alters the immune system, making people much more vulnerable to infections and diseases.

HIV is found in the body fluids of an infected person and is passed from one person to another through blood-to-blood contact, sexual contact, or from a mother to her child during pregnancy or through breast feeding.

The United Nations says 34 million people lived with HIV/AIDS and 1.7 million died from the disease in 2011.