There’s been a lot of virtual chatter about the the hidden rooftop houses of New York City, a fascinating brand of creative resourcefulness that would make great fodder for a sequel to The World Beneath the City, a 1959 book that contains passages describing the alligators and other discarded pets rumored to roam the dark labyrinth of sewers and tunnels on which our city is built.

Rooftop architecture is the enchanting, dreamy counterpart to the world below and it’s a design solution that is as practical as it is delightful. After all, in today’s increasingly crowded and overbuilt cities, there is nowhere to go but up. Proof that topping up doesn’t have to be in the form of an obscenely tall, terrifyingly austere skyscraper, click through to check out our favorite rooftop projects from around the world, including some of New York’s high up hidden houses. Let us know in the comments what you think about building on top of other buildings. Is it the way of the future?

Didden Village by MVRDV — Rotterdam, The Netherlands

Image credit: ArchDaily

LoftCube by Werner Aisslinger — Berlin, Germany

Image credit: design werner aisslinger; xupeko

Growing House by Tonkin Liu with Richard Rogers — London, England

Image credit: Michael Tonkin via Tonkin Liu

Jerwood Space Extension by Munkenbeck + Partners — London, England

Image credit: Jerwood Portal; Munkenbeck + Partners

Central Park West Rooftop Garden — New York, New York

Image credit: Norman McGrath via Inhabitat

Roof Top Office by dagli + atélier d’architecture — Dudelange, Luxembourg

Image credit: Jörg Hempel Photodesign via MOOD

Kunsthülle LPL Performance Space by Office for Subversive Architecture — Liverpool, England

Image credit: architecture-buildings

Hut-on-a-Roof by hût architecture — London, England

Image credit: hût architecture

Icosa Village Pod — Williamsburg, Brooklyn

Image credit: Folded Homes

A Room for London by Design Initiatives — London, England

Image credit: designboom

Cape Cod House — East Village, New York

Image credit: Nick Carr; Inhabitat

Rooftop A-Frame — New York, New York

Image credit: Inhabitat; Nick Carr