I've explored the world's most luxurious airport, complete with a butterfly garden and a pool. It's my favorite layover spot.

Changi’s luxury is spread across four terminals.

The Changi Skytrain connects terminals 1, 2, and 3, while Terminal 4 can be accessed via bus.

Most of the airport's main attractions are located in Terminals 1 and 3, where I spent most of my time. Terminal 2 was closed during my visit, but it has reopened with a digital waterfall and sky that mirrors the time of day.

I enjoyed a movie at the free cinema.

Among the easiest ways to pass the time at Changi is Terminal 3's free movie theater, complete with cushioned chairs and a big silver screen.

No ticket is needed — but you will have to settle for whatever movie is playing at the time. During my visit, films including Encanto, Venom II, and Fantastic Beasts were shown on a loop.

Changi houses 1,000 live butterflies.

There is no shortage of greenery throughout the airport, which is maintained by a team of horticulturalists.

One of the main beauty staples inside the transit area is the butterfly garden. Terminal 3's two-floor enclosure hosts 1,000 butterflies that represent nearly 50 species.

I could watch colorful butterflies snacking on fruit while some were cocooned, waiting to hatch.

You can nap in special sleeping areas.

While I was too busy exploring to sleep, tired passengers could use the airport's "Free Snooze Lounges," available in every terminal.

The 27/4 space is intended for short naps. For those who want a more private or longer sleeping experience, Changi has lounges and transit-area hotels with nap rooms available for a fee.

Changi is among the few airports in the world with an outdoor pool.

One of Changi's on-site hotels is Aerotel, which is inside Terminal 1. Transit passengers can book a room or pay about $20 for access to the outdoor pool and hot tub. This was my favorite plane-watching spot.

The pool deck overlooks the tarmac, is full of lush greenery and chairs, and hosts a bar, showers, and a gym. The pool opens at 12, but hotel guests can access it earlier.

You can eat authentic Asian food from the indoor market.

There is no shortage of food inside Changi, but my favorite spot is the Singapore Food Street in Terminal 3. Over a dozen individual stalls serve food from countries like Vietnam, China, and Singapore.

I ordered a feast for myself and my travel companions, including dumplings, meat skewers, noodles, vegetables, and Singapore's famous laksa. Everything was delicious.

For those who prefer an American meal, there is a Burger King and a Subway neighboring the market.

There is no shortage of luxury shopping.

I don't have a single designer item in my closet, but that doesn't mean I wasn't impressed with the myriad duty-free luxury stores throughout Changi.

There were beautiful Louis Vitton shops, complete with grand entrances and colorful lighting. Customers could also shop at stores like Dior, Swarvoski, and Gucci.

I preferred the more local shops, like TWG Tea, where I bought some tea to take home to my family.

Changi’s most famous attraction is Jewel.

Changi hosts Jewel, a giant amusement park-like garden area with activities, food, and shopping. Flyers will have to leave the transit area to explore Jewel and then reenter the airport before their connecting flight — though some people visit Jewel as a day trip from the city.

The main attraction in Jewel is the rain vortex, which is seven stories high and the world's tallest indoor waterfall.

Jewel houses a Canopy Park with games and scenery.

Customers visiting Jewel can use the booths or kiosks to book tickets to the various attractions, including a hedge maze, a ropes course, and a topiary walk.

The activities can be fun for adults but are more geared toward kids, so Jewel is a perfect place to spend time with children during a long layover.

Underneath the airport is a 'carnival.'

One thing I was surprised to find at Changi is an "underground carnival."

There were restaurants, a playground, and huge stores with souvenirs. Locals told me they also do their grocery shopping here.

There's always something to do.

Once you exhaust the main attractions, there are niche perks scattered around the airport. Terminal 3 has a koi pond and a four-story slide, for example.

There is also a set of bikes that flyers can use for exercise while simultaneously charging their phone.

Plus, flyers with long layovers can take advantage of the free tours available — passengers just need to register and meet minimum layover time requirements.