Museums in the United States present a distinctly American perspective, demonstrating ideals such as freedom of expression, open access to information and tolerance for diversity.

No longer mere repositories for the culture of the past — collectors of ancient artifacts and works of art or tracers of an idea’s evolution — U.S. museums offer visitors new experiences that often spur them to generate their own ideas.

Toby Kamps, curator of modern art for the Menil Collection in Houston, believes that just as freedom of expression is at the heart of any artist’s project, museum directors themselves are giving voice to a freedom to present “powerful works — works born out of celebration and protest, of love and anger.”

As a consequence, according to Brandon Brame Fortune of the National Portrait Gallery, U.S. museums today offer “an amazing diversity … of artist and subject, an ethical and political diversity, a geographical diversity.”

U.S. museums explore the history of particular Diasporas, such as the Chinese American Museum of Los Angeles or the Mexican American Cultural Center of Austin, Texas. Some focus on visual culture, such as the Museum of Modern Art in New York or the Art Institute of Chicago. There are museums that engage visitors on science-related topics, such as the Exploratorium in San Francisco and the Pacific Science Center of Seattle.

U.S. museum directors strive to afford more people access to art and ideas. Admission to one-third of all museums is already free, and more are adopting this model. U.S. museums that do charge fees typically offer a free day once a month.

The Smithsonian Institution, for example — the world’s largest museum complex with 17 facilities in Washington focusing on diverse subjects — is free and open to the public 364 days a year. The Smithsonian illuminates the extent Americans value not just information, but access to it.

U.S. museums reflect the country’s diversity, not only through programs and exhibitions, but as evidenced by the visitors they attract. Passing through the organized chaos of the Smithsonian’s National Museum of American History on a typical day, one might see a father debate the merit of the penny coin with his young son or a couple trading facts about the light bulb. In the austere halls of the Art Institute of Chicago, there might be teenagers sketching from works by the masters or college students taking in sculptures they had seen only in books. As visitors to U.S. museums arrive from every part of the globe, a painting’s merits are likely to be discussed in Spanish, French, Chinese or Arabic.

Curators are constantly finding new ways to engage these diverse audiences. They install interactive exhibitions for children and host provocative speakers for adults. They invite participation and encourage debate.

“Rather than being authorities with all the answers, sometimes the most important role the museum can play is asking the right questions,” according to Kathleen Ash-Milby, curator with the National Museum of the American Indian in Washington.

An exhibition at the National Museum of American History, “Slavery at Jefferson’s Monticello,” is an example. It details the lives of hundreds of people Jefferson owned, forcing museum-goers to consider the complexities of a man who wrote the Declaration of Independence, which calls slavery an “abominable crime,” while enslaving Africans. Recorded interviews featuring Jefferson’s slaves and their descendants are juxtaposed with the desk at which Jefferson drafted the declaration.

The resulting dialogue, similar to animated conversation by visitors to museums across the country, Ash-Milby says, bears witness to “the true richness of our culture.”

• There are at least 17,500 museums in the U.S. — nearly 5,000 more museums than McDonald’s restaurants.

• U.S. museums receive an estimated 850 million visitors per year. The four major sports leagues welcome fewer than 132 million.

• One-third of U.S. museums do not charge admission.

• The median cost of admission to a U.S. museum is $7. The median cost of serving a visitor is $31.40.

• Private donations are the largest source of operating income for museums.