Some of this valley’s so-called “hidden gems” truly are hidden, often in plain sight. Some are well-known, even advertised. Others are reserved for those in the know.

Jonathan Ullman, president and chief executive officer of The Mob Museum, looks over Prohibition-era artifacts in the speakeasy at The Underground at The Mob Museum in downtown Las Vegas on Saturday, April 14, 2018. The basement-level exhibition of the Prohibition era features a working distillery and speakeasy where attendees can stay for a drink. Chase Stevens Las Vegas Review-Journal @csstevensphoto

A room hidden by a wall-length portrait in the speakeasy features 1920s artwork at The Underground at The Mob Museum in downtown Las Vegas on Saturday, April 14, 2018. The basement-level exhibition of the Prohibition era features a working distillery and speakeasy where attendees can stay for a drink. Chase Stevens Las Vegas Review-Journal @csstevensphoto

Sara's at Mabel's BBQ on Wednesday, Jan. 16, 2019, at Palms, in Las Vegas. Benjamin Hager Las Vegas Review-Journal

The tunnel painted by NYC-based graffiti artist CES pays homage to New York City’s iconic street art of the '80s and '90s through layers of tags representing graffiti legends such as SEEN, P-NUT, BLAZE at Greene St. Kitchen at the Palms. (Clint Jenkins)

Laundry Room boozologist Dan Marohnic adds a flaming finish to a drink at the Commonwealth at 525 E. Fremont St. (Bill Hughes/Las Vegas Review-Journal)

Laundry Room boozologist Dan Marohnic adds a flaming finish to a drink at the Commonwealth at 525 E. Fremont St. (Bill Hughes/Las Vegas Review-Journal)

The Laundry Room in the back of Commonwealth has a menu that features more than 40 Prohibition-era cocktails. Credit: The Laundry Room

Guests who venture through the Ghost Donkey door will find a south-of-the-border-themed party room. Credit: Thomas Hart Shelby

Mezcal bar Ghost Donkey, at The Cosmopolitan of Las Vegas, is in a secluded space with a door adorned only with a festively attired donkey. Credit: Thomas Hart Shelby

Las Vegas is known for bright lights, neon and LED signs advertising its top attractions large and loudly. But the city is also synonymous with secrets and insider tips. And some of this valley’s so-called “hidden gems” truly are hidden, often in plain sight. Some are well-known, even advertised. Others are reserved for those in the know. But they’re all part of a hot new trend: the Las Vegas speakeasy. Here are five great spots you might miss if you’re not careful.

Ghost Donkey: When The Cosmopolitan of Las Vegas added a food court-style collection of restaurants on its second floor dining promenade in 2018, it reserved a secluded space behind the communal dining area for the New York mezcal bar Ghost Donkey. Today, guests brave enough to venture through an isolated door in the back, adorned with nothing more than a festively attired cartoon donkey, will find a south-of-the-border themed party room. The entire place is an Instagrammer’s dream. But the money shot is an only-in-Vegas order of nachos topped with summer truffles. The Cosmopolitan of Las Vegas, cosmopolitanlasvegas.com

The Underground: It should come as no surprise that the valley’s most historically accurate speakeasy is in the basement of The Mob Museum. Ostensibly a museum exhibit examining the history of Prohibition, The Underground seamlessly blends education, alcohol and fun. Guests enter by day via a staircase from the museum’s lobby. At night, however, visitors walk down a mildly sketchy (but completely safe) staircase, accessible from a driveway on the east side of the building, and ring the bell. Those who provide the doorman on the other side of a sliding peephole with the weekly password (availabl via social media), will gain entry to enjoy cocktails served inside hollowed-out books, and shots of moonshine brewed in the on-site still. 300 Stewart Ave., themobmuseum.org

The Laundry Room: While many local speakeasies feign exclusivity, access to this secluded spot in the back of Fremont Street’s Commonwealth is truly difficult to secure. Admission is reservation-only, and it usually books up two to three weeks in advance. Those reservations can only be secured by texting a secret number. Most customers are friends of past guests who had the number passed along. But if you spend any serious time downtown chatting with employees of various bars, you will probably find someone willing to share that number. Those who succeed are treated to an interactive, period-specific experience with bartenders who pride themselves on getting to know each customer and creating cocktails to suit their taste. 525 Fremont Street. commonwealthlv.com

Sara’s: Michael Symon’s Mabel’s BBQ in The Palms is a massive, casual party spot with communal portions of food served on metal trays, and an outdoor patio equipped with ping-pong and shuffleboard tables, with a stage for live music. Tucked behind a wall without any sign betraying its presence is an elegant throwback known as Sara’s that seats 40 to 50 people in its small lounge and patio areas. The limited dining menu spotlights elegant interpretations of classics, many prepared or finished tableside, while a formally dressed mixologist holds court at a gorgeous walk-up bar. To get the tap on the shoulder that will allow you to pass through its hidden door, you’ll need to call ahead for a reservation, or speak to your casino host. The Palms, mabelsbbqlv.com.

Greene St. Kitchen: OK, Greene St. is not a secret, especially when you consider the billboards The Palms put up to advertise it and its poolside brunch. But there’s still some speakeasy wow factor to the entry, which is hidden behind a Coca Cola machine in the resort’s vintage video arcade. Swing it open to reveal the entrance to a cavernous restaurant decorated with world-class street art. (Yes, that’s a real Banksy hanging behind the hostess stand.) The hip, eclectic menu offers some great dishes — from Jidori chicken skewer appetizers to a Fruity Pebble-flavored, space alien-shaped baked Alaska that arrives at the table in a cloud of dry ice. The Palms, greenstkitchen.com.