Cocaine is one of the most potent, natural stimulants available.  

The following is after reading about Cocaine  & Crack on DrugFreeWorld.org, drugabuse.gov and Medlineplus  

There is documented proof that the Coca leaf was chewed to increase heart rate over 5000 years ago.   In the late 1800's and early 1900's Cocaine was thought to be a miracle drug and prescribed for a wide-variety of ailments.  A google image search, shows many of the indications including to treat gum soreness, depression, dietary aide, hangovers and stomach problems including Coca Cola, now a soda, which was originally a green elixir filled with Cocaine. 

Also in the early 1900's, Nasal Damage due to snorting Cocaine and Cocaine related deaths (aka overdose) started being reported.  In the late 60's and 70's, it started to become the drug of choice in Hollywood.  Throughout history, it's recreational use was highest in the upper class (those with money) but all that started to change in the early 80's when it's popularity skyrocketed.  Like Heroin in Philadelphia or Chrystal Meth on Southern Mid-Western states, Cocaine was the drug of choice.  

Then came Crack.  

In the early to mid 80's, Crack was created from Cocaine.  It's a highly potent, highly addictive form of the drug that initially gives it's user an intense high never to be reached again due to tolerance.  It's cheaper than Cocaine and easily affordable (at first) compared to the higher prices of Cocaine. Thus, it's move to lower class and minority neighborhoods took off.  The 1991 R-Rated movie "New Jack City" starring Wesly Snipes, Judd Nelson, Ice-T, Chris Rock and Mario Van Peebles (among other stars of the time) was loosely based on real life information about the rise of Crack in New York City's housing developments.  It's hip hop and r n b filled soundtrack was amazing for the time and many people saw the movie as much as a documentary (although not all true) as it was  entertainment.   

The Cocaine and Crack Epidemic, as the CDC put it, actually is the main reason why Nancy Reagan started her "Just Say No: anti-drug campaign and the Federal Government upped their "War on drugs" as funding for the FDA, DEA, ATF, and Border Patrol/Customs was increased.

One of the saddest things anyone can ever do in life, is walk through a nursery intensive care unit where babies are being cared for who were born from crack addicted mothers.

Although the epidemic in Philadelphia is "over" (people still use but it's nowhere close to Heroin Addiction), It's important to educate ourselves about the dangers of the drug so that in the future, you will not try it yourself.