(CNN) -- From minibars to pillow menus to 24-hour butlers, today's hotels have turned every indulgence and convenience into a standard necessity.
But this wasn't always the case. Not long ago, those little shampoo bottles that people now love to swipe didn't even exist.
Nor did in-room iPads or fingerprint recognition technology. Oh, the humanity!
Thankfully, over the last 100 years some innovative hotels have helped pave the way for these modern accommodation marvels.
Because of their foresight and progressiveness, these ground-breaking properties forever changed the future of the industry, enabling guests to expect -- and demand -- increasingly more.
Electric Xmas tree: Hotel del Coronado, San Diego
Currently celebrating its 125th anniversary, this scenic beachside resort made jaws drop back in December 1904 when it unveiled 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.
Hotel del Coronado, 1500 Orange Avenue, Coronado, CA; rooms from $321; +619 435 6611
En-suite bathrooms: The Goring Hotel, London
Renowned for having hosted various members of the royal family throughout the years (Kate Middleton even stayed here the night before her wedding to William), the Goring is widely considered one of the top luxury hotels on the planet.
However, when it first opened back in 1910, what really wowed the travel industry was that each bedroom was fitted with en-suite bathrooms -- something that had never been seen before at any other accommodation property.
Needless to say, The Goring's early guests were delighted not to have to queue up for the toilet any longer.
The Goring Hotel, Beeston Place, London, UK; rooms from $455: +44 (0) 20 7396 9000
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 increasingly 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.
Boston Park Plaza Hotel, 50 Park Plaza at Arlington Street, Boston, MA; rooms from $100; +617 426 2000
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 plethora 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.
The Waldorf Astoria, 301 Park Avenue, New York, NY; rooms from $288; +212 355 3000
Minibars: Hilton Hong Kong
Countless thirsty travelers saved and their wallets thinned -- all thanks to one Hilton executive and Siegas, the German company that invented the refrigerated minibar in the 1960s.
In 1974 an executive from Hong Kong Hilton (closed in 1995) was inspired to stock overpriced liquors in all 840 rooms, and lo the loved/hated minibar was globalized.
The minibar invention was said to have led to a 500% increase in room-service drink sales and a 5% boost to the company's net income that year, according to the Atlantic.
Though the Hilton closed, the company has a presence in Hong Kong with the Conrad.
Conrad Hong Kong, Pacific Place, 88 Queensway, Hong Kong; rooms from $382; +852 2521 3838
Air conditioning: Adolphus Hotel, Dallas
Dallas, Texas can get quite hot and humid throughout the summer months, with temperatures often soaring into the high 90s F.
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.
Adolphus Hotel, 1321 Commerce Street, Dallas, TX; rooms from $103; +214 742 8200
Soap and shampoo: Four Seasons London at Park Lane, London
Forgot to pack shampoo for your getaway? Not to worry -- most hotels these days have plenty of mini toiletry bottles on hand to keep you lathered up 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 amenities 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!
Four Seasons London at Park Lane, Hamilton Place, London, UK; rooms from $639; +44 (20) 7499 0888
Carbon neutral: Wolgan Valley Resort, Australia
As the first carbon neutral-certified resort in the world, this high-end, multi award-winning getaway in Australia's Blue Mountains single-handedly introduced the concept of responsible luxury travel to the world in October 2009, proving that green, eco-friendly accommodation could also be indulgent.
Wolgan Valley Resort, 2600 Wolgan Road, Wolgan Valley, Lithgow, NSW; all-inclusive rooms from $1,652; +61 2 9290 9733
Kristen McKenzie heads up HotelsCombined.com's team of hotel experts and specializes in hospitality industry trends. The hotel search site compares prices and data from hundreds of travel sites with a database of 400,000+ hotels. HotelsCombined.com