After I return from a trip, I find that certain memories fade while others actually become brighter over time. My time in Las Vegas last November is a perfect example: I couldn’t tell you what day I visited a particular casino, because those windowless rooms were hard to distinguish from one another after a while. But that makes the memory of the day I visited the Hoover Dam stand out even more.

The Hoover Dam is 30 miles southeast of Vegas, and it’s impossible to overstate how important it is to the entire southwestern corner of the country. It’s also hard to believe how gorgeous it is: while the dam was constructed between 1931 and 1936 to control the mighty Colorado River and generate hydroelectric power, its builders created a beautiful monument as well. The concrete dam and buildings have a distinct Art Deco appearance, enhanced by decoration using motifs of the region’s Native American tribes.

There’s a fascinating museum on the site, which explains everything from the complicated politics of building the dam to the engineering of the structure. (I have little understanding of engineering, but the description of the workings of the concrete arch-gravity dam — in which gravity and the design of the horizontal arch work together to carry the water load — were well-explained.) When you walk to the middle of the dam, you straddle the border between Nevada and Arizona, and depending on what time of year you visit, a single step can put you into a different time zone. There’s also a very touching memorial on the site, dedicated to the many workers who died while constructing the dam. “They died to make the desert bloom,” reads the large plaque in their honor.

Another memory that stands out from that trip is dinner at the Border Grill, which is located at Mandalay Bay. When I called them to ask if they’d be able to accommodate me, I discovered that they have a separate gluten-free menu. (This fact isn’t mentioned on the restaurant’s website; the original Border Grill restaurant in Santa Monica doesn’t have a separate gluten-free menu, though they can accommodate celiac diners, too). It turned out that I had plenty of choice. For a starter, I had the queso fundido, a deliciously gooey mix of melted manchego, panela, asadero, and Oaxacan string cheeses, served with chorizo and roasted poblano peppers. My main course was the most memorable: I had the Kobe beef tacos, which were spicy from being marinated with guajillo chiles but also sweet with the addition of pineapple salsa. Whenever I go back to Las Vegas, I know which two spots I’ll want to hit first.

Border Grill Las Vegas [address] In Mandalay Bay Resort and Casino, 3950 Las Vegas Blvd. South, Las Vegas, NV [tel] 702-632-7403 [fax] 702-632-6945 [web] www.bordergrill.com

Border Grill Santa Monica [address] 1445 4th St., Santa Monica, CA [tel] 310-451-1655 [fax] 310-394-2049 [web] www.bordergrill.com