Half the fun of watching "Lost" is trying to unravel the mystery.

The plot of the popular ABC drama has more than its share of riddles wrapped in enigmas, but for Hawai'i residents, an equally rewarding braintwister is guessing where the cameras rolled.

Location scouts have combed O'ahu for unique backdrops ever since the Hawai'i-based "Lost" began filming in the Islands in 2004. They've found places that gave the show's creative team a wide range of possibilities — locations that could be transformed, with carpentry and computer magic, into major cities, dusty deserts and snow-covered streets.

Savvy Islanders can usually tell where "Lost" has been, and not because they saw the trailers on the street.

Or can they? With the sixth and final season about to start, The Advertiser wants to test your local knowledge. Starting with the photo on this page, we'll publish a photo from a "Lost" location each Sunday through Jan. 24. E-mail us your answers.

FAMILIAR FACE

Our location photographs were shot by Ryan Ozawa, 35, a webmaster for real estate listings site Hawaii Information Service who is also known for his online social networking and blogging on "Lost."

Ozawa has been to the set so many times, the crew knows him. Although sometimes he's been asked not to take a photo — and even if he is in a public place, he'll oblige the request — he's frequently allowed to stay and watch.

"When I leave my camera in my car, we're good buddies," he said. "When I have my camera around my neck, the game is on. But if there is anything I want to stress is that it is cordial. It is cat and mouse, but we are friendly."

The extensive location work makes "Lost" a visual treat to watch, in Ozawa's opinion; it may be television, but it has a "cinematic" feel, he said.

"It is fundamentally important," he said. "You can tell when something is shot on a soundstage, no matter how good the lighting is. There is something about an actual street. Real depth."

Successfully transforming a location into what a script demands is never easy, but the show's scriptwriters have often made the task even more difficult, said Jean Higgins, the executive producer for "Lost."

The first time she and her staff were "really stumped" was when two characters were set to meet in Buffalo, N.Y., in the middle of winter. Finding the backdrop was easy — the episode was shot in a Chinatown alley.

CREATING SNOW

The snow took more creativity: "Lost" turned to a shipping company with a machine that fills cargo holds with finely ground ice.

"We had to send dump trucks to the machine and then bring the ice to the street," Higgins said. "We had maybe six hours of shooting before it all melted away. It worked so well, we did it again on Merchant Street and called it Berlin."

Higgins, who has worked in movies and television for nearly 40 years, loves the challenge of working on location.

"It's like a giant puzzle and there is no right answer except how good are you, how good can you possibly be?" she said.

LOCATION, LOCATION

Most viewers don't appreciate the importance of a good location, said Walea Constantinau, commissioner for the Honolulu Film Office.

"Location has so much influence on the final product," she said. "When it is done well, as 'Lost' does it, it is done so subtly you don't realize how much that setting does to propel the story forward or give you insights into the characters."

While O'ahu's tropical rainforests and beaches serve as the primary set for the fictional island where "Lost" takes place, the many subplots of the show required location scouts to use their imagination.

With its diverse architecture, ethnic communities and urban landscapes, O'ahu is a malleable resource, Constantinau said — standing in for New York, Tunisia, Thailand and Korea. The show's producers estimate they've used hundreds of locations.

Digital imagery is also used, enabling "Lost" to plop the Sydney Opera House at the end of the Ala Wai Canal and replace an ocean view from Michel's with Niagara Falls.

"More than any other show filmed in the Islands, 'Lost' has taken a look at what resources are in the location department and has used them so nimbly and creatively, that it has opened people's eyes to Honolulu and the island of O'ahu as a production center," Constantinau said. "They have all these different settings that are supposed to be all over the world, and they have to do them here."

But you knew that already, right?