Looking like something out of a creepy fairytale, this little black house hovers in the air beneath the arch of an old railway bridge, a spindly ladder reaching down into the fallen leaves. If you weren’t expecting it to be there and happened upon it while on a walk, you might be a bit shocked to see it seemingly floating in space, its skylights glinting in the sun. From far away, you can’t see how it could possibly be supported, lending it a somewhat supernatural appearance.

The steel cables that support the structure become apparent as you walk up, and the ladder is usually hidden off to one side, requiring passersby to look around a bit for a way to get up.

But if you did happen to be brave enough to approach it and climb the ladder, not knowing what you’d find inside, you’d be greeted with a bare-bones but cozy hut from which to survey the surrounding woods, complete with a loft and a wood stove.

Set in an area that’s 15 minutes walking distance fro the city center of Pardubice, Czech Republic, the installation takes advantage of stark scenery left behind by disused infrastructure, aiming for the feel of a mysterious military complex.

Created by H3T Architekti and photographed by Maritna Kubesova and Tomas Rasl, ‘Flying Black House’ is a temporary installation daring passersby to give in to their curiosity, even if it makes them feel like the foolish protagonist in a horror movie.

A work of art, genius and incredible effort, half of this replica structure appears to hang in mid-air, seeming at once a perfect aesthetic fit for its surroundings and completely disconnected from the laws of physics.

British artist Alex Chinneck and his crew spent over 500 hours and had to construct a 4-ton counterweight to balance this faux building in the sky. What appears to be solid stone is in fact a steel-framed copy of an historic structure also found at Covent Garden (the original is nearly 200 years old), held in place by the innocuous-looking green structure with red wheels pushed up against one side.

Chinneck is well known for his architecture-centric optical illusions, with this particular piece created as a play on the area’s “performance culture” – its proximity to theaters and performance spaces.

The construction process required a painstaking attention to historical details and materials in addition to grafting the appearance of age, wear and tear onto the fake structure. Another significant challenge: the seemingly haphazard breaking and slicing of everything from stones to windows and their frames.

From the artist: “The hovering building introduces contemporary art to traditional architecture, performing a magic trick of spectacular scale to present the everyday world in an extraordinary way. My objective was to create an accessible artwork that makes a harmonious but breath-taking contribution to its historic surroundings, leaving a lasting and positive impression upon the cultural landscape of Covent Garden and in the minds of its many visitors.”

How do you fit an entire new neighborhood for 65,000 people, complete with offices, schools and streets, into the already congested and overdeveloped island of Manhattan without knocking anything down? Hover it. That’s the plan for Hudson Yards, the largest private development project in U.S. history, which will be erected on a super-strong platform over an existing active rail yard between Chelsea and Hell’s Kitchen.

The whole massive, incredibly heavy thing will barely touch the ground, resting on 300 concrete-sleeved steel caissons inserted 40-80 feet into the bedrock. Borrowed from bridge-building techniques, these supports will hold up a slab that will serve as the foundation of six skyscrapers, 100 shops, 20 restaurants, a school and 14 acres of parks.

The 26-acre West Side Yard over which this development will be built is a critical part of New York City’s transit system, serving overflow Long Island Railroad trains during rush hour with 30 tracks and space for storage and maintenance. Luckily, its original developers in the 1980s realized that one day the space would be prime for redevelopment, and left a gap around the edges of the yard just big enough for structural members to be installed without interrupting traffic.

Since the trains will still be active while Hudson Yards is under construction, actually getting everything into the ground will be a bit of a challenge. The builders plan to sink the caissons in sections and then attach them to 100-foot trusses whenever there’s a window of opportunity in between moving trains.

Gizmodo got an early look at the plans and has a series of mesmerizing gif images of exactly how everything will come together. It’s an interesting example of developers finding space for something new in a bustling metropolis without disturbing existing functionality, and even arguably improving a lot that many find an eyesore. The final phase of the city’s High Line park, set to open later in 2014, will connect directly to Hudson Yards, which should be complete by 2024.

A fantastic feat of architectural trickery, this anti-gravity ante-room installation appears to hover in thin air and open up into nothingness. It sports a single point of contact with the ground below – a ladder propped against it, ostensibly placed to access the amazing space.

The piece was designed by Leandro Erlich (some images by Martin Argyroglo) of Argentina for an annual art festival in France, but the artist is known elsewhere as well for his vertigo-inducing work.

The ladder is the secret behind supporting this tenuous chunk of building, being much stronger than it first appears. A set of furniture stacked on it appears to be waiting to be taken to the top.

The Shaft was set in the Sean Kelly Gallery of New York and took visitors through a sideways version of an elevator void. Stuck Elevator at the same gallery gives one a peek at one of those jarring experiences one hopes to avoid for live.

Using mirrors, Erlich has also turned entire buildings on their side and made them into interactive urban playgrounds, as covered here previously and seen above.

Out of four recent proposals for a radical overhaul of Penn Station in New York City, this concept by Skidmore, Owings & Merrill LLP is far and away the most dramatic – and arguably the most inspiring as well.

Drawing on the success of The High Line, an elevated park in the same city, this project solution from SOM proposes lifting city life to new heights and integrating a new version of Madison Square Garden, boldly suspended in midair.

Below, the main station itself sits as a dome over the underground transit hub. Meanwhile, the mega-block is anchored by towers at its four corners, with offices occupying the lower floors and residential stories above.

On the one hand, this multi-layered result consolidates central activities around a newly-refocused core. On the other, it opens up shared green park space on a series of levels, blending intentionality with optionality.

While conceptually simple, the design is … challenging from an engineering standpoint, to put it mildly, and more idealistic than realistic at this point. Hanging so much structure over such a distance stretches the limits of the imagination, but that practical weakness is also the visionary strength of the proposal, for better and worse.