One thing is certain: The world’s cities are going to keep growing. The question is: How do we ensure our cities grow in a positive way?

That’s the 21st Century urban design challenge, and there are as many ideas as there are people our cities. “Urbanized,” playing at the Northwest Film Forum through January 19, is a look at some of the urban design ideas developing around the globe, from the slums of Santiago to the bike trails of Bogota to art on condemned buildings in New Orleans.

If you are a huge StreetFilms geek (like me!), some of what you see will not be news. But there are many moments of surprise and wonder. Beautifully shot, the film attempts to tell the massive story of modern cities through a series of vignettes from around the world.

The highlight for me was probably the film’s interview with Bogota’s Enrique Peñalosa, who makes fantastic statements about transportation equality. Standing on a bus rapid transit platform (Bogota has the REAL thing, not faux-BRT like RapidRide), he points to a bus and notes that there are 100 people in it. Therefore, it deserves 100 times the road space of a single car, and that why there are so many bus-only lanes on Bogota’s crowded streets.

Likewise, he takes the film crew for a bike ride, praising bikes for being extremely economical and encouraging good public health. He defends paving a network of bike trails through the city by saying that bicycling should be given equal respect as driving. A person in a $30,000 is equal to someone on a $30 bike, he says.

In the end, I definitely wish there were more bikes in the film, but I just really like bikes. As a story, “Urbanized” is not quite as gripping as 2007’s surprisingly fascinating “Helvetica,” one of director Gary Hustwit’s other design documentaries (I haven’t seen “Objectified,” his second in the design doc trilogy). But if you are at all interested in how city design works and the positive directions it could be headed if we want it to be, then be sure to check it out.

Due to popularity, the NW Film Forum (Pike and 12th on Capitol Hill) has extended the run through January 19. See the NWFF website for the schedule.