It's been a fascinating decade of concept cars. Retro styling is still going strong, but a lot of the time it's just a hamfisted attempt at using nostalgia to ease in the idea of electric drivetrains. There are also the wildly futuristic concepts that try to redesign the wheel (literally), but ultimately it's always a circular thing. Finally, there are the great concept cars. The ones that show off a great idea, an eye for contemporary design, or both together. These are the most exciting examples we've seen in recent history, and we would love to see all of them make it into production.

1. Mazda RX-Vision

Mazda loves to stoke rumors of a new rotary engine car a couple of times a year. And we can't get enough of it. In 2015, just three years after the end of the RX-8, Mazda started the cycle again with its gorgeous RX-Vision concept. Unfortunately we'll never see a rotary engine providing drive to a production car again, but we would be fine with any drivetrain for what looks more like a fluid GT car than an all-out sports car.

2. Renault Trezor

Renault showed off a long, sleek two-seater GT concept in 2016. It's a concept car in the fullest sense, representing a petal in the French company's Life Flower design strategy. The concept bases Renault vehicles around life stages, and in this case, it's love. As well as perpetuating French stereotypes, the Trezor's canopy lifts for entry, and driver and passenger have to climb in, so we like to think that represents the idea that love isn't always graceful. The highlight for us is the wraparound window, though. Hopefully, it will become a thing on production cars in the not-too-distant future.

3. Volkswagen Atlas Tanoak

Crossovers with a truck bed could well be the next big thing, and Hyundai is first to market with the small Santa Cruz. But in 2018 Volkswagen showed off its Atlas Tanoak Concept, describing it as "a progressive pickup whose habitat is the wide-open spaces of North America." It's named after a tree found on the US Pacific coast, including around Santa Cruz. It appears automakers have been seriously thinking about smaller, more leisure-focused trucks for some time, and the Volkswagen Atlas would make a great one.

4. Audi skysphere

If the future is autonomous, Audi has an answer for enthusiasts. As we know, driving in traffic is boring. The skysphere (lower case 's' is Audi style) is a sleek fabric-topped convertible concept that is shapeshifting depending on whether it's in autonomous mode or manual driver mode. In human driver mode, the hood, fenders, and front wheels contract by 9.8 inches to reduce the length and wheelbase of the car. The change is similar to going from an Audi A8 to an RS5 Coupe as the steering wheel and pedals deploy. Adding to the excitement, the concept is powered by a single motor on the rear axle generating 624 hp and 553 lb-ft of torque.

5. Nissan IDX

The Nissan IDX represents disappointment as Nissan wanted to put the retro style rear-wheel-drive sport compact into production but couldn't come up with a business case for a new plant to build it. The problem is that the only Nissan plant that could handle longitudinally-mounted engines and both rear- and/or all-wheel drive production already built the GT-R and the 370Z at the time. That time was 2013, and the concept still looks as good as it did then. Perhaps it's time for Nissan to revisit the idea if the R35 GT-R isn't coming back for another model year.

6. Genesis Mint

"The Mint Concept disconnects the physical dimensions of the vehicle from its positioning as a premium product, translating the city car of the past to today," said Luc Donckerwolke at the 2019 New York Auto Show. "The Mint Concept is a designer's Occam's razor that challenged us to visualize a scaled-down interpretation of our signature aesthetic."

Don't bother trying to interpret the above as it's complete nonsense. It is neither a word-for-word translation of past city cars nor follows the rule that entities should not be multiplied beyond necessity. However, it is a gorgeous small car with practical design elements, such as smooth, clean bodywork with the matrix pattern wheels and lower trim. That trim also guides air to cool the underbody battery pack. The rear-hinged scissor doors replace a trunk lid for access to the cargo space, but we're not convinced how practical that would be in reality day-to-day. Mainly it's on this list because it's one of the best-looking concept cars we've seen.

7. Porsche 917 Racer Concept

If you're someone that follows concept cars and don't recognize the Porsche 917 Racer Concept, don't worry. You didn't forget it. Porsche did. It was a study made by "a small team of designers and engineers" in 2013. It's also the least complete concept in this list as it's just a clay model. Porsche says no further work was done due to its entry into the LMP1 class of the FIA World Endurance Championship in 2014. That's when it was put into storage and forgotten about until the 50th anniversary of the original 917 race car. The concept's livery and race number are taken directly from the Le Mans-winning 917 that set the pace for Porsche's commitment to racing.

8. GFG Style Kangaroo

Revealed at the 2019 Geneva Motor Show, the GFG Style Kangaroo will never go into production, which is a shame. On the surface, it looks like a standard supercar designed in a wind tunnel and given a few flourishes to show it's Italian. However, it's a road racer and an off-roader speeder. In Racing mode, it has a 5.5-inch ground clearance. In Road mode, it sits 7.5-inches from the ground. However, if you want to go off-road with those big chunky tires, then it raises to 10.2 inches - only an inch or so less than a Land Rover Defender in its tallest setting. According to designer Giorgetto Giugiaro and his son Fabrizio, the Kangaroo is all about transitioning between track, sand, dirt, and snow to be the ultimate toy.

9. Peugeot e-Legend Concept

We put Peugeot's e-Legend Concept up there with Nissan's compact sport coupes, harking back to the automaker's 504 Coupe styled by Pininfarina in the 1960s. However. Peugeot showed the e-Legend as an electric car with advanced autonomous tech at the 2018 Paris Motor Show. Like the Audi skysphere, Peugeot sees its car as a self-driver that can also be self-driven. However, the e-Legend is a little more realistic, all the way down to 456 horsepower and 590 lb-ft of torque being delivered to all four wheels and sprinting from 0-62 mph in under 4 seconds before topping out at 137 mph. It's also absolutely gorgeous.

10. Mercedes-Maybach Vision 6 Cabriolet

A lot of modern concepts hark back to former glories and it's hard sometimes to tell how much is about nostalgia and how much is about having a spoonful of sugar to help the electric drivetrain to go down. In this case, four electric motors deliver 750 horsepower to the wheels of a two-seater measuring almost 20 feet in length. And somehow, the cabriolet version of the Mercedes-Maybach Vision 6, unveiled at Pebble Beach in 2017, is even more beautiful than the coupe. On the outside, anyway. The inside is a little try-hard for our taste.