The Women's March on Washington started as an idea for a protest from one woman, and quickly grew into a massive demonstration set for Inauguration Day. The march, which will go on despite challenges by the Trump transition team, will be a protest against a president who bragged about harassing and assaulting women and whose administration will work quickly to roll back gains in women's rights.

Over 150,000 people from across the country have registered to join the Women’s March on Washington in protest of President-elect Donald Trump’s attitude and behavior toward women and other marginalized people.

Begun by Theresa Shook, a retired attorney in Hawaii, the march now stands to be one of the largest demonstrations to take place in protest of a presidential inauguration.

The march has become a catch-all for a host of liberal causes, from immigrant rights to police killings of African Americans. But at its heart is the demand for equal rights for women after an election that saw the defeat of Democrat Hillary Clinton, the first female presidential nominee of a major party.

“We plan to make a bold and clear statement to this country on the national and local level that we will not be silent and we will not let anyone roll back the rights we have fought and struggled to get,” said Tamika Mallory, a veteran organizer and gun-control advocate who is one of the march’s main organizers.

The event has faced a number of obstacles, including rules banning it from popular protest sites in D.C. like the Lincoln Memorial. But the group has since secured a permit to march on the morning after Inauguration Day, and is in the process of raising money to secure the rest of the organizational needs and permits. And at least 1,000 buses from different cities across the United States have been scheduled to take people to the march.

The fact that the largest inauguration day protest ever will greet Trump on his first morning as president is a welcome sign for activists all over the United States. Trump’s messaging throughout the primaries and the campaign were distinctly misogynist, what with his vulgar and violent comments about grabbing women by their genitals and video of him attempting to kiss women who clearly did not want to be touched.

Trump has also placed people in positions power who believe that women who need birth control can somehow get it for free without government assistance and who have been extremely hostile to places that provide necessary health services for women and minority-gender populations.

This march will be a massive show of protest and resistance against these and myriad other grave concerns regarding the incoming administration. And it will surely be only the first of many such events to come.