(CNN) -- What's the best thing you could stumble upon when transiting through a major international airport?
A Cinnabon passing out free samples?
A security checkpoint with no line?
Not bad choices, but for unexpected pleasure they hardly measure up to a dress made entirely of Hello Kitty dolls or a Kamen Rider escorting your humdrum slog to the departure gate.
Those last two items are part of Japanese Toys! From Kokeshi to Kaiju, the current exhibition at the SFO Museum inside Terminal 3 at San Francisco International Airport.
Debuting in November 2013, the exhibit has become such a success -- the most popular exhibit ever for the museum -- that its run has recently been extended through mid-May.
"Travelers love it. Many people have really been caught by surprise as they walk through the terminal and see the colorful kaleidoscope of Japanese toys," says Nicole Mullen, curator of exhibitions at SFO Museum.
Atomic dragon meets world-conquering cat
With dozens of colorful items, the exhibit presents the evolution of Japanese toys, from kokeshi (wooden dolls dating at least to the 1800s) to Godzilla to everyone's favorite mouthless cat.
Popular items also include vinyl kaiju (monster) figures and novelties from the futuristic TV series "Ultraman," which premiered in 1966.
"For a show such as this one, some people will have a memory of a particular character from their childhood, such as Hello Kitty or Godzilla, that they get particularly excited about," says Mullen.
The toys supply a window into Japanese customs, legends and history.
Early Japanese folk toys were made by local craftsmen.
After Japan opened to the West, however, toys that emulated their German and American counterparts began to emerge, such as classic wind-up and battery-operated toys.
The thriving Japanese movie, television and manga industries that followed World War II spawned a legion of iconic characters.
According to Megan Callan, assistant curator of museum affairs for SFO Museum, more than 4.6 million passengers have walked through SFO Terminal 3 since the exhibit premiered.
"Seen through the lens of social media, this exhibit is our most popular to date, with daily references through sites like Twitter and Instagram," says Callan.
The museum has created the hashtag #JapaneseToys.
Airport museums thriving
Exhibits of art and cultural pieces are becoming the norm at many U.S. airports, with some 20 or more airports regularly hosting exhibits.
San Diego International Airport, Philadelphia International Airport and Phoenix Sky Harbor International Airport are noteworthy among airport exhibit aficionados.
But SFO Museum is the only one accredited by the American Alliance of Museums.
Since opening in 1980, SFO Museum has grown from one gallery space to more than 20 galleries hosting 40 exhibits each year.
Dewey Blanton of the American Alliance of Museums calls SFO Museum the "most ambitious one" among all airports with exhibition programs.
"The great works of art the San Francisco Airport museum showcases send the message to visitors and travelers that San Francisco is a center of culture, they value culture and art," says Blanton. "This is a very educated and sophisticated city you are coming to."
For non-travelers, one chance to see it
For those not traveling through SFO before the Japanese toys exhibit closes in mid-May, the Japan Society of Northern California is organizing a panel discussion and guided tour on April 22.
Registration is open to anyone -- for non-travelers, the tour is the only chance see the toys in person.
Among other speakers, toy collector Mark Nagata will talk about the history of Japanese toys and their influence on contemporary culture.
Japanese Toys! From Kokeshi to Kaiju; on display in SFO Terminal 3 until mid-May.
Exhibition tour registration here; April 22; 6-9 p.m.; registration deadline 11:59 p.m., April 14; advance registration required, no walk-ins permitted due to security restrictions.