Two historical interpreters review inventory in the fort store. Ledgers from trading posts like Bent’s give historians and re-enactors vital clues into the equipment frontiersman relied on from year to year.

(Megan Verlee/CPR News)

Ranger John Carson has spent the past three years helping plan the Fur Trade Symposium at Bent’s Old Fort. This week, those efforts came to fruition when almost 70 people portraying fur traders came to Bent's Old Fort in southeast Colorado for the 2015 Fur Trade Symposium.

Re-enactors are committed to really living out history, but authenticity doesn't come cheap: Replica firearms generally cost well over $1,000 and historically-accurate leathers can come in at $20 a square foot. Read and listen to the full story to learn why they do it.