The Library of Congress — the world’s largest library — was under pressure. Visitors to the Capitol Visitor Center, which opened in December, could easily spill over to the library’s Thomas Jefferson Building. A tunnel connects the library to the CVC, which expects at least 800,000 visitors in its first year.

“We’re going to have people coming over from the Capitol that have no idea where they’re going. They are just going to walk over here unsolicited. We don’t have the capacity to handle that volume of traffic,” said Robert Sokol, project manager for the library’s new program designed to improve the experience of visiting the LOC.

To address the surge in tourists, the LOC has created a “Passport to Knowledge,” a pocket-sized informational booklet that allows visitors to map out their tour of the library’s vast collections. The passport, which is free, can be found at interactive kiosks called MyLOC stations.

“They could come over here, be handed a passport and flip through and will have a sense of what this place is,” Sokol said.

Each passport has a bar code that is unique to each user. “The passport is sort of the key to the door. When you put this key to a MyLOC station, it remembers everything you’ve done and there’s a personal account associated with the passport,” Sokol said.

When visitors insert the passport into a MyLOC station, it will ask them to type their name and e-mail address onto the touch screen. They can then browse through each exhibit and add a particular exhibit to their “collection.” Later, visitors can go to the MyLOC.gov Web site and enter their e-mail address and password to access their personal collection.

“If you are building your own collection, you are essentially building your own library. And you can start collecting the treasures of the library in your own account,” Sokol said. Unlike a regular library though, of course, visitors do not have to return their collections.

Among the LOC’s prized collections are two rare Bibles on the first floor of the Jefferson Building: a Gutenberg, the first book printed using movable type, and a giant hand-lettered Bible produced in Mainz, Germany, in the mid-1450s.

Upstairs is Thomas Jefferson’s Library. Of the 6,487 books that Jefferson sold to Congress for $23,950 in 1815, only two-thirds are left. The rest burned in an accidental fire on Christmas Eve in 1851. Also on the second floor is an exhibit, “Exploring the Early Americas.” It includes the 1507 Waldseemüller map, considered America’s birth certificate, where the name “America” first appeared.

To make children’s visits more exciting, the LOC created “Knowledge Quest,” a game that lets participants discover the hidden meanings in the library’s collections.

The Minerva mosaic, for instance, contains objects that symbolize the powers of the Roman goddess. Minerva is not only the goddess of wisdom and learning, but also of war. She’s also the guardian of civilization. Children can find the mosaics that symbolize those powers.

“This is a way where kids can learn a little bit about the space. The way we’ve designed all of our games is that no matter where you go, you have to accidentally think a little bit,” Sokol said. With the passport, he added, “they’ll walk away with a memory of what they’ve done” and continue the game at home.

“Passport to Knowledge” is part of the $23 million program, the “Library of Congress Experience,” a marriage of interactive and traditional exhibit experiences. “Part of our thought process in putting this together is that adults and kids absorb information differently,” said Jennifer Gavin, senior public affairs specialist.

Because the library only issues cards in order to check out books to Members of Congress and staff, Gavin said the passport is a good way for visitors to have “something to connect personally” with the library.

The Library of Congress is America’s oldest federal cultural institution. Its collections include more than 32 million books and other print materials, 12.5 million photographs, 5.5 million pieces of sheet music, 5.3 million maps, 2.9 million recordings and 61 million manuscripts.