In Juarez, Mexico, a group of American university students build houses. In Quito, Ecuador, medical professionals spend two weeks correcting cataracts – pro bono. In Kenya, handfuls of Hollywood stars try "making a difference" at orphanages. At the same time, these volunteers are having a travel experience. They stay in hotels, eat in restaurants and try to bond with locals. They are volunteer traveler hybrids known as voluntourists. Can they really see the world and save it too?

A rising tide of do-good travelers

"Voluntourism," writes David Clemmons, founder of VolunTourism.org, "is the conscious, seamlessly-integrated combination of voluntary service to a destination with the traditional elements of travel and tourism – arts, culture, geography, history and recreation – while in the destination."

Over the past 20 years, companies and organizations have sprouted up to meet mushrooming demand for these experiences. In kind, journalists and researchers have also begun investigating the impacts. A recent ABC report, for example, examines the downsides of medical missions.

The benefits for the voluntourist are clear: meaningful cross-cultural exchanges; the chance to contribute to a vital humanitarian cause or project; and insights about life from people with different perspectives. But critics have legitimate questions. Can cross-cultural exchanges also lead to greater misunderstanding and loss? Can well-intentioned individuals on short-term schedules make a lasting difference? Is it really about the destination, or just an ego trip? The solution is complex.

In the urban landscape of Buenos Aires, Argentina, fauna is fantastically diverse. I love watching the human wildlife. My favorite species is the callejero, or street circus performer. In parks around the city, they set up their slack lines. They hang their long, silk telas from trees to practice aerial dance. Juggling pins fly. The callejeros spend hours in the parks, simply teaching and learning circus arts.

Each year, callejeros from Buenos Aires and all over Latin America convene outside the city. The event is called La Convención Argentina de Circo, Payasos y Espectaculos Callejeros (Argentinian Convention of Circus, Clowns and Street Performer Shows), or La Convención for short. It's a grand affair that gains a bigger crowd each year. The November 2011 Convención attracted around 900 participants.

The event was founded in 1996, when the circo nuevo (new circus) phenomenon began to grow in Argentina, mirroring movements and conventions that were going on in Europe's bohemias.

"La Convención was created to satisfy the need for space. We wanted a space for meeting, learning, exchange and union – by artists and for artists," comments El Payaso Chacovachi, one of the founding clowns. That first year, 250 people and one small circus tent started something special.

Now, fifteen years later, this has become one of the greatest street-level shows on earth (or at least in the southern hemisphere). La Convención has always been a five-day marathon of workshops, contests, parades and performances. On day one, the big tents go up – two real circus tents.