5 Hotels that changed their industry

     (CNN) -- From minibars to pillow menus to 24-hour butlers, today's hotels have turned every indulgence and convenience into a standard necessity.

   

Electric Xmas tree: Hotel del Coronado, San Diego

Currently celebrating its 125th anniversary, this beautiful beachside resort made jaws drop back in December 1904 when it presented the world's first electronically lit, outdoor Christmas tree.

Back then, candles were still commonly used to don yuletide trees and electric Christmas lights were a rarity.

Hotel del Coronado's extravagant holiday display amazed guests at the time and set the stage for the lavish hotel light exhibitions we now see today.

In-room radios: Boston Park Plaza Hotel, Boston

When this Boston property opened back in 1927, it was the first hotel to provide guest radios in each room, a feature that had never been offered on such a wide scale before.

To put this in perspective, the radio in the late 1920s was extremely popular among Americans and was bigger and bigger becoming a main source for news, entertainment and music -- similar to what the TV and Internet would become for later generations.

It wasn't until 1933 that two-thirds of Americans would own a radio set at home, so to have one available in one's hotel room in 1927 was quite a prospect.

Room service: The Waldorf Astoria, New York City

The iconic Waldorf Astoria is renowned for many things including its Art Deco motifs, Waldorf salad and a lot of celebrity guests.

But what truly revolutionized the hospitality industry was its introduction of room service in the early 1930s.

The novelty of such a convenient 24-hour service was an instant hit amongst the Waldorf's high-end guests and it wasn't long before other properties across the globe begin following suit.

As a result, lodgers everywhere can now comfortably chow down in their bathrobes without having to do much more than push a button.

Air conditioning: Adolphus Hotel, Dallas

Dallas, Texas can get quite hot and humid throughout the summer months, with temperatures often grow into the high 90s.

So in 1950 when the Adolphus became the first hotel in the world to offer central air conditioning, we can only imagine how thankful its sweaty guests must have been.

In-room air-conditioning for warm climate hotels has since become a commonplace comfort.

Soap and shampoo: Four Seasons London at Park Lane, London

Forgot to pack shampoo? Not to worry -- most hotels these days have plenty of mini toiletry bottles on hand to keep you soppy throughout your stay.

Prior to 1970, however, hotel guests would have been out of luck.

It wasn't until the Four Seasons London at Park Lane opened its doors that lodgers were first introduced to the concept of bathroom services such as shampoo.

And even then, the very first shampoo offerings at the Four Seasons Park Lane were plastic little sachets that were difficult to rip open. Don't take those handy little hotel bottles for granted again!