Two years after the National Woman’s Party moved into 144 Constitution Avenue Northeast, a three-story, red-brick building steps from the U.S. Capitol, Alva Belmont, the benefactor of the women’s suffrage group, declared: “May it stand for years and years to come, telling of the work that the women of the United States have accomplished; the example we have given foreign nations; and our determination that they shall be—as ourselves—free citizens, recognized as the equals of men.”

The building, today known as the Sewall-Belmont House and Museum, was designated a national monument on Tuesday.

“The house tells the story of a century of courageous activism by American women,” President Obama wrote in a presidential proclamation.

“I want young girls and boys to come here—10, 20, 100 years from now—to know that women fought for equality, it was not just given to them,” Obama said in a speech at the house late Tuesday morning. “I want them to come here and be astonished that there was ever a time that women could not vote. I want them to be astonished that there was ever a time when women earned less than men for doing the same work.”

The Sewall-Belmont House & Museum will be renamed as the Belmont-Paul Women’s Equality National Monument, in honor of Belmont and Alice Paul, who founded the National Women’s Party in 1917 and would become the key strategist of the campaign for the women’s vote in the 1910s.

As a young woman, Paul studied in England, where she joined the Woman’s Social and Political Union, the original suffragettes organized by Emmeline and Christabel Pankhurst.  Paul returned to the United States in 1910 and began using the tactics she learned abroad to organize rallies, parades, and petitions. In 1917, during World War I, members of the National Women’s Party began picketing outside the White House, holding signs that read, “How long must women wait for liberty?” The 19th Amendment, which gave women the right to vote, was ratified three years later. Paul would go on to write what is known today as the Equal Rights Amendment, a proposed amendment to the U.S. Constitution guaranteeing equal rights for women, from the party’s Constitution Avenue headquarters; introduced in 1923, it passed Congress in 1972 but was not ratified by the states. “When you put your hand to the plow, you can’t put it down until you get to the end of the row,” she once said. Paul worked for the women’s-rights movement until her death in 1977.

The Belmont-Paul Women’s Equality National Monument is the second national monument that specifically commemorates women’s history. The first, the Harriet Tubman National Monument in Cambridge, Maryland, was designated by President Obama in 2013. Counting the new addition, just nine out of 411 U.S. national-park sites honor women’s history, according to the National Parks Conservation Association.

The designation occurred on Equal Pay Day, a date recognized by women’s and civil-rights organizations as symbolic of how far into the year women must work to earn what men earned in the previous calendar year. Obama designated April 12 National Equal Pay Day on Tuesday. In the United States, women earn 79 cents for every dollar men earn. The wage gap is greater among minorities; black women are paid 60 cents and Latinas are paid 55 cents for every dollar paid to white men.

The Sewall-Belmont House is listed on the National Register of Historic Places. In 1999, the house was one of the first four recipients of funding under the Save America’s Treasures legislation, introduced by former President Bill Clinton and designed to preserve historical sites and works. The other three were the Declaration of Independence, the Constitution, and the Star-Spangled Banner. Last summer, Senator Barbara Mikulski, a Democrat from Maryland, introduced a bill that would add the Sewall-Belmont House to the national-park system. The legislation was supported by 13 of 20 women then serving in the Senate. “Not a single one of us would be here without Alice Paul and the National Woman’s Party,” Mikulski said at the time.