For 10-year-old Mary, the last time she saw her 8-year-old sister Jessica was when they were removed from their biological parents' home two months earlier and placed in separate foster homes.

That all changed last month at Disneyland.

"Mary arrived first and was eagerly awaiting Jessica's arrival," Victoria Diaz, a volunteer with a nonprofit organization called Together We Rise, told "Good Morning America." "About 10 minutes later, Jessica arrived and the two sisters instantly sprinted toward each other with tears in their eyes! It was such an incredible moment to experience and a wonderful reminder of why this event is so important."

The sisters' reunion was one of 350 sibling stories at "Disney Days," an event held each September through Together We Rise. The organization's mission is to "improve the lives of children in foster care, who often find themselves forgotten and neglected by the public."

Many of the people who work for and volunteer for the organization were also part of the foster-care system.

"All youth in attendance are currently in the US foster care system, a system in which a minor has been placed into a ward, group home, or private home of a state-certified caregiver, referred to as a 'foster parent' or with a family member approved by the state, due to varying instances of abuse and/or neglect," Together We Rise told "GMA" in an email. "Due to the overwhelming number of youth who enter the foster care system in America every day, many of the attendees have been separated by some or all of their biological siblings."

PHOTO: Siblings separated in foster care reunite at annual event.
Together We Rise
Siblings separated in foster care reunite at annual event.

The all-expense-covered day at Disneyland includes meals, snacks, souvenirs and personal photographers to capture every special memory from their day. After the event, attendees are sent a personalized memory book to remind them of the magical time spent with their siblings at Disneyland.

This year's event, held Sept. 21 and 22, is in its sixth year.

"Originally, 'Disney Days' started as a way to do something positive for kids in foster care on my birthday," Danny Mendoza, founder and CEO of Together We Rise, told "GMA." "Each year the event grows and is a testament to our supporter’s belief in childhood memories. Children should be with their siblings and they deserve to enjoy being children together."

Luis, 8, enjoyed everything about "Disney Days," but he said there were two moments that really stood out.

"My favorite part of the day was seeing my brother and having my first churro!" Luis said.

The Walt Disney Company is the parent company of ABC News. Disneyland is not a sponsor of or affiliated with "Disney Days."