"Nyaope" drug addicts gather nightly in "Highrise Park" on the edge of Hillbrow, an inner-city Johannesburg neighbourhood with a notorious reputation.  A crude form of heroin reputedly cut with anything from anti-retrovirals to rat poison to pool cleaner, nyaope is either injected or smoked with a mixture of cannabis and tobacco. The drug is cheap (about R20/ $1.70 per "round") and devastatingly addictive - it produces a brief high, but then leaves the user with vicious withdrawal symptoms, constantly searching for the next high.