Street medicine providers and homeless outreach workers who travel into Las Vegas’s drainage tunnels have noticed an uptick in the number of people living underground, and it can be difficult to persuade them to come aboveground for medicine and treatment

Constructed in the 1990s and measuring some 600 miles, the tunnels provide flood control for the city and outlying communities. Homeless outreach workers said 1,200 to 1,500 people live in them. Many have constructed elaborate shelters, often out of plywood and scraps of metal or brick below the casinos that define the Strip.