We remember a few nights spent camping that were pitch black. Of course, we always had flashlights to help find the tent.
But, on those unfamiliar campgrounds, the device only illuminated so much.
Kevin Robert Frost, CEO of amfAR, The Foundation for AIDS Research, understands completely.
"That which is within the light is clear," he says. "But you never know how big the dark is."
In the mid-80s, researchers in France and the United States first shone light on HIV. Twenty-five years, millions of deaths and billions of dollars later, it seems we're still wandering around in the dark.
In recent years, promising trials have failed and new infections still outpace the number of people we put on antiretroviral treatments. We have to wonder how far away is a cure, a vaccine - anything. But, while the search seems hopeless, it's those at the centre of the research who are most optimistic.
"There is new and exciting research leading us down interesting paths," says Frost. "We have a long way to go but I'm more optimistic now than I have ever been."
Many researchers say wondering why we haven't yet conquered the AIDS-causing virus is fair - the world is impatient in the fact of this terrifying disease. But while the darkness is immeasurably large, even our failures have made the microbe itself clear.
With most viruses, there are people who survive them and develop a natural immunity. To replicate this defense, scientists use a piece of the virus to trick the body into developing this immunity.
But, with HIV, no person has ever successfully cleared it. That means the body's immune system is inadequate rendering the traditional methods for developing a vaccine ineffective.
So, scientists must develop a new approach that actually improves and enhances the immune system.
"I don't want people to lose hope when we say we're going back to the basics," says Dr. Carl Dieffenbach, director of the Division of AIDS with the National Institute of Allergy and Infectious Diseases. "We could really turn this epidemic around and it's our responsibility to prove it."
Neither Frost nor Dieffenbach have a timeline for discovering a cure or a vaccine. But, both says promising research lies in prevention.
Many new infections can be prevented through behavioral modification, like condom use and reducing sex partners - but also through biomedical research.
Microbicide gels are promising. The gel can be given to high-risk individuals and applied before intercourse to reduce the risk of initial transmission. Just last month, researchers announced one gel had successfully reduced the risk of transmission in monkeys. Plus, a formula called PRO 2000, reduced risk by 30 percent in women - a small percentage but with two million new infections each year, one that could potentially save thousands of lives. Dieffenbach says the next fives years will be a key period for discovery.
"Combine this with condom use, education and testing and we're got a multi-dimensional attack that could get the pandemic under control," says Dieffenbach. "Vaccine may be a one-shot deal but we need to do something now with the information we have."
That one-shot deal is the proverbial holy grail of medical research. That doesn't mean it's not out there. So, in the meantime, we could be focusing on preventing new infections.
Although setbacks have forced scientists to go back to the drawing board, they go back with a wealth of information that brings the darkness into focus. No matter which c-word we use - be that cure or control - we move to closer to clarity.
"I'm not a fortune teller but I do believe we can do this," says Frost. "I don't believe there is a false hope in saying that."