President Donald Trump's executive order mandating extreme vetting for travelers from Muslim countries caused dozens of people from Iraq, Iran, Sudan, Libya, Somalia, Yemen and Syria to be detained over the weekend. But it also inspired activism, motivating protesters to flood American airports and immigration lawyers to offer their services for free as families scrambled to understand the impact of Trump's action.

If you're looking to join the resistance, here are four ways to get involved:

Donate money. Organizations like the American Civil Liberties Union, which called Trump's ban a "war on equality" and filed a related lawsuit Saturday on behalf of two Iraqi men with immigrant visas, were soliciting monetary gifts to continue their fight. The ACLU told the Washington Post Monday it received more than $24 million in online donations over the weekend. You can send them money here.

You can also check out refugee-focused groups like the International Rescue Committee, which recently revealed an emergency appeal to raise $5 million to support people's "necessary and immediate aid on arrival and beyond — including housing, cultural orientation, health care, education, employment, and immigration services," according to its website. Donate here.

Drop off food at airports. Attorneys across the country have set up tables in airport terminals where they're working nonstop to help refugees, immigrants and other travelers. If you're headed that way, bring water bottles or snacks to drop off. 

Call your representatives. Make sure your voice is heard in Congress by reaching out directly to the politicians who represent you. Several lawmakers turned out to airport protests and news conferences over the weekend, including Sen. Chuck Schumer, D-N.Y., and Rep. Jamie Raskin, D-Md. Others, like Sen. John McCain, R-Ariz., condemned the ban in interviews and on social media.

Let them know what you think of their involvement by contacting them. Find your elected officials' phone numbers and email addresses here. When you reach someone, make sure to calmly explain what issue you're addressing and why you felt moved to call them, according to the Leadership Conference.

Welcome refugees in your everyday life. Spend your money at refugee-run businesses or start the process of becoming a United Nations volunteer, either in the U.S. or abroad. Get involved in a local refugee mentorship program like RefugeeOne or Vibrant Pittsburgh.