Every December for the last decade, thousands of people come to see the elaborate Christmas displays that illuminate Houston’s posh River Oaks neighborhood. But getting the elegant houses ready for the masses is more than an afternoon with a ladder and extension cords—these installations are big business.

Cost estimates from installers range from $5,000 on the low end to $100,000 for a truly wild setup that you might find on a country estate or commercial building. At least one business in the Houston area—We Light the Holidays—runs a full-service decoration service, planning displays with customers and storing extra lights during the offseason. But primarily it’s businesses like lawn care, pest control, and air-conditioning companies that get in on the lucrative light installations just for the season.

Steve Trauber’s display—which features a live Santa and elves—is situated in the heart of River Oaks, and is one of the most popular among crowds. Trauber hires Tiffany and Gordon Lester, a husband-and-wife duo who run a feed store near Austin for most of the year, to install his lights. Neighbors describe Trauber as a pioneer of truly elaborate Christmas displays in River Oaks. He started putting up lights around seven years ago, and a friendly competition with a neighbor soon ensued. “Next year we did more, and he did more,” he says. “It was kind of like an arms race.”

That neighbor moved away, but the lights go on. “It’s gotten better and better every year,” Trauber says. “This year’s the best ever.”