Researchers discovered traces of the bacteria that causes syphilis in human remains from long before Christopher Columbus' travels in Finland, Estonia and the Netherlands.
Cases of the sexually transmitted infection (STI) syphilis are rising in the U.S.
Brazil's religious right, bolstered by conservative president Jair Bolsonaro, are pushing cuts to sex education amid skyrocketing rates of HIV and syphilis.
Syphilis and other STDs are on the rise in the U.S. and drug use and unprotected sex may be to blame.
The Kanamara Festival is held annually on the first Sunday of April and raises money for research into sexually-transmitted diseases.
African-American men were included as part of clinical testing but excluded from treatment.
The AHF called Tinder "a digital bathhouse for millennials" in a press release about the billboards.