The saying "everything old is new again" has a twist when it comes to buildings that have transformed so much from their original purposes that the new venues are almost unrecognizable from their historical origins. Here's a look at several new event-oriented venues that have undergone extreme makeovers.

St. Louis Union Station Hotel, Curio Collection by Hilton, unveiled a $40 million transformation in September. The 539-room hotel is in what was one of the largest and most ornate railway terminals in the United States, with some guest room floors designed with a railroad theme. Built in 1894 and converted to a hotel in 1985, this national historic landmark in downtown St. Louis is notable for its massive Grand Hall, a lobby lounge area with 65-foot-high ornate vaulted ceilings on which a 3-D light show is projected nightly.

Housed in a building that used to be the Charles Street Jail, the Liberty hotel completed $11 million in renovations to its guest rooms in March. The 298 newly designed rooms were done by interior designer Bill Rooney. Famous inmates of the Charles Street Jail (which was also known as the Suffolk County Jail) included James Michael Curley and Malcolm X. Their jail cells were a far cry from the property's luxury suites, which include the 2,220-square-foot Ebersol Suite with amenities such as floor-to-ceiling windows, living room, dining room, butler pantry, library, master bedroom, bathroom, and a 300-square-foot patio.

Open since June, Ford Amphitheater at Coney Island Boardwalk is a 5,000-seat venue in Brooklyn for live entertainment. It's located in the former Childs Restaurants Building, a New York City landmark that was completed in 1923. After Childs left the property in 1952, a candy factory occupied the building for the next 50 years until the New York City Council approved plans to redevelop the property in 2013. The covered outdoor venue includes a terrace-level concessions area and a rooftop cafe with casual American dining. In 2017, the venue will open a ground-floor restaurant and 40,000 square feet of publicly accessible landscaped open space that will include a park and playground. Live Nation holds a long-term lease to operate the amphitheater, which is the cornerstone of the Seaside Park and Community Arts Center. Hospitality services are provided by Legends.

Set to open in the spring of 2017, Nopsi Hotel, New Orleans is a 217-room property in the city's Central Business District. The hotel is in a nine-story brick building that opened in 1927 and used to house the energy company New Orleans Public Service, Inc., known as Nopsi. Building and Land Technology is developing Nopsi Hotel, New Orleans, which will have a regionally inspired restaurant, 10,000 square feet of architecturally significant indoor and outdoor meeting space, and a rooftop pool and bar.

Magnolia Hotel Houston opened in 2003 in the former Houston Post-Dispatch Building, which was built in 1926 and is listed on the National Register of Historic Places. The 314-room hotel, which is owned by Stout Street Hospitality, has a rooftop pool, jacuzzi, and a lounge with billiards. Located downtown close to Minute Maid Park, the Houston Aquarium, and the theater district, the hotel is set to become Tribute Portfolio's first property in Texas when it converts in January.

Magnolia Hotel Denver, also owned by Stout Street Hospitality, will become Tribute Portfolio's second hotel in Colorado and first hotel in downtown Denver after its conversion in October 2017. Located in the former American National Bank Building, a landmark edifice from 1910, the 297-room hotel was restored in 1995 to reflect the building’s original appearance with terra cotta details and a replicated corner clock. The hotel's multimillion-dollar renovation will include the creation of 51 guest rooms and a presidential suite.

Open since June, Jack’s Shop Kitchen is an American restaurant in Ruckersville, Virginia, that is located inside the former Massey Tractor Showroom, which opened around 1940. The building later became a manufacturing plant for Wrangler jeans. Antique dealers now occupy the floors above and below the restaurant. The 5,000-square-foot eatery can seat 90 in the main dining room area and another 60 in a private space.

According to Trump Hotels, about $200 million was spent to convert the Old Post Office building on Pennsylvania Avenue into Trump International Hotel, Washington, D.C., which debuted in September. Opened in 1899, the building was Washington, D.C.'s main post office until 1914. The property survived two near-demolitions in the 1920s and the 1970s, and underwent extensive renovations in 1976 and 1983. In 2013, the U.S. General Services Administration chose Trump Hotels to develop the property. The hotel has 263 guest rooms, 35 suites (including three presidential suites), a BLT Prime by David Burke restaurant, 38,000 square feet of meeting and event space (including a 13,200-square foot Presidential Ballroom), and a 10,000-square-foot Spa by Ivanka Trump and fitness center.