Stacy Nick / KUNC

At Christmastime, Santa Claus gets all kinds of requests - from dump trucks to Barbie dolls to Teenage Mutant Ninja Turtles.

But no matter what the must-buy toy of the season is, there’s one that always embodies the epitome of the holiday season.

“Christmas is when all of America are model railroaders, they just don’t know they are,” said Michelle Kempema, executive director of the Colorado Model Railroad Museum. “Trains and Christmas -- we put them under our trees. We see them when we go to the malls. We go, and we look at train layouts in store windows. It’s a joy for us.”

Daniel Cima / American Red Cross.

The American Red Cross launched First Aid for Opioid Overdoses, a new online course aimed at teaching volunteers how to respond to a known or suspected opioid overdose.

Katie Lazar / Serve Colorado

Denver ranked fifth among large cities with the highest number of residents who choose to serve in AmeriCorps programs.

Every year the Corporation for National and Community Service, which administers national service and volunteer programs, ranks the cities and states that produce the most AmeriCorps members.

Barbara Stewart, CEO of the Corporation for National and Community Service, said there's a spirit of service and volunteerism in Denver that's infectious.