May 5 is the National Day of Awareness for Missing and Murdered Indigenous Women (MMIW). Here's how activists are marking the day.

Each year, Indigenous rights advocates commemorate the National Day of Awareness for Missing and Murdered Indigenous Women to honor the Indigenous women and girls in the US who have disappeared and lost their lives.

The date was chosen to mark the birthday of Hanna Harris, who was 21 years old when she disappeared from a reservation in Montana on July 4, 2013. Several days later, she was found raped and murdered.

Stories like Hanna's are far too common. In fact, studies have shown that the homicide rate for Indigenous women and girls on reservations is ten times greater than the national average.

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But even those numbers don't tell the full story. The Urban Indian Health Institute pointed out that there is a huge research gap when it comes to Indigenous women living in urban areas.

The institute sought to fill that gap in a 2017 study, in which they found that there had been at least 506 MMIW cases in cities across the US. Those numbers are likely an undercount, they said.

Many of the crimes against Indigenous women and girls go unreported and unsolved due to a number of factors, including discrimination, legal barriers, bad record-keeping, and lack of media coverage.

To call attention to the ongoing MMIW crisis, advocates are urging Americans of all backgrounds to honor the victims by wearing red. They also encourage people to organize or attend a vigil or rally in your community and contact federal and local authorities to demand legal reforms and greater accountability for these crimes.

The National Indigenous Women's Resource Center is asking everyone to participate in a Twitter storm to call for justice for MMIW and their families.