Of all the many made-up holidays out there, this is one we should be really grateful for: National HIV Testing Day is June 27. As much as HIV and AIDS are not the frightening death sentences they once were for many (though they still are in impoverished populations), they're still a threat.According to the Centers for Disease Control , nearly 1.2 million Americans are living with HIV and one in eight of them doesn't know it. Young people ages 14 to 24 are significantly affected , too: People ages 13 to 24 accounted for one in five HIV diagnoses in 2014 and 80% of those were gay and bisexual males.Not knowing means not knowing you can spread it — and not knowing you need to seek treatment. Testing is the only way to find out if you're HIV-positive. More than 45,000 people in the country find out they're HIV-positive every year and 90% of HIV infections in U.S. could have been prevented. The CDC recommends that everyone between the ages of 13 and 64 get tested at least once in their lives and more often if you meet certain risk factors The good news is that on National HIV Testing Day, there are free testing events with extended hours all over the country. Go to AIDS.gov to find a testing site near you.