Years ago in McAllen, Texas, an old abandoned 124,500-square-foot Walmart superstore was renovated and put to new use as the largest single-floor public library in the United States. Across America, many malls have emptied out and thousands of abandoned big box stores sit empty, including hundreds of former Walmarts. Some, though, are getting creative new leases on life, becoming community markets, indoor tracks, gaming spaces, museums and more.

In McAllen, aisles that used to divide shoppers have been adapted or replaced to serve the community. The old Walmart is packed with computer labs, public meeting spaces, a cafe, an art gallery, a used bookstore and more. In other small towns and suburbs around the United States, the generic promise of all-in-one convenience big box stores once offered is being realized in new and site-specific ways.

Designers at the research and development lab of KTGY Architecture + Planning in Los Angeles have particularly inspiring aspirations for old shopping centers: plug-and-play modular prefabs that subdivide big empty boxes into transitional housing for the homeless. This is not the first time architects and designers have attempted creative solutions to this pervasive problem, but it’s notably ambitious.

The firm’s Re-Habit project involves housing as well as support spaces and services fit into unused spaces in big boxes or individual shopping outlet stores like Sears and JCPenney. Self-supporting communal residences, where occupants rotate chores like working in the kitchen or keeping the dining hall clean, are coupled with facilities to providing training and potentially even employment.

Where some might see empty space, others see opportunity. The large, flat roofs of big box stores, for example, are ideal for rooftop gardening, open-air recreation and solar panels — these kinds of uses would pair well with a project like Re-Habit. Many big boxes have outdoor plaza areas (not to mention giant parking lots) that could accommodate small pop-up shops and food carts, too.

Adaptive reuse in the realm of big retail is forward-thinking but also proven concept. Big boxes have been turned into commercial gyms, corporate offices, schools, churches and (yes, this is true) even a SPAM Museum. Whatever the project, it takes vision and resources to turn such dauntingly huge structures around as well as an understanding of the potential pitfalls and unique opportunities of this peculiar building typology.

Such large-scale conversions tend to work best when they take advantage of big box assets and work within their limitations. Generally, big box stores reside in huge buildings that are located in prime spots, often along highways, which makes them accessible but can also make them hard to fill up. They generally have a lot in common, like orientations that lend themselves to being sectioned into bays and limited natural light, features that can work well for things like libraries. Often, though, the best option is simply whatever best fits community needs, which is often a mixed-use program that can more effectively fill out a bigger interior.

Big retailers may be more prevalent in suburbs, but there are some prime urban examples as well. A series of converted Sears plants in major US cities offer a range of realized visions for what big old commercial buildings can become. In Minneapolis, for instance, a massive mail-order Sears plant and retail store was abandoned by its makers for years before being turned into the Midtown Exchange, a busy structure full of restaurants, stores, offices, condos and apartments. It took a lot of players to make this work, including invested city officials and both public and private funding from various sources.

Often, these conversions speak to the character of the cities in which they are located. In Seattle, a place known for its coffee, the city’s old Sears plant now houses the Starbucks headquarters. In Los Angeles, land of Hollywood, a deserted Sears was used for film shoots during its derelict years but is on its way to becoming a residential and commercial hub. Boston and Memphis have converted Sears projects, too — uses are mixed in both cases.

While the individual projects vary, each city has something in common having turned a similarly monumental structure into something new. These various projects fill in gaps and address needs that are fundamentally local. Together, they represent a series of blueprints that other cities can look to, whether they have Sears plants themselves or are simply looking for ways to deal with big old commercial spaces.

Existing examples can provide paths forward, but other architects have grander visions, too, some of which have yet to be tried. Designers could, for instance, build around big boxes on all sides, then turn the central old structures into community hubs or parking lots or productive green spaces. Another option is to tear down sections of roofs and facades, dividing big boxes up into smaller and more manageable units while leaving structural supports intact.

There is no one-size-fits-all solution for disused spaces, but cities, towns and sururbs looking for inspiration have both real-world examples and conceptual designs to draw on. In some sense, the core recipe never changes — for any big transformation project, municipal officials, citizens, developers and designers will always have to come together to find best-fit solutions on a case-by-case basis.

Unlike other arts, architecture is generally limited by practical matters, including what materials can do, how things stand up, and in most cases (but not so much this one) an array of challenging local building codes.

A firm in Mumbai, India called sP+a developed this vaulted brick library roof with a playful purpose in mind, allowing people to walk up and over it like a bridge to cross the school grounds it sits in the middle of — on a cool evening, the heat-absorbing bricks also create a cozy open-air reading area.

The idea is conceptually simple: the ground simply extends up and over the top. In most places, a railing would be required, if the steepness didn’t stop the design in its tracks, but not here.

“On our first visit to the site it was interesting to see geodesic structures built by an engineer for a few of the school buildings, we were somewhat encouraged by this to pursue a project that followed from a construction intelligence,” explains sP+a. “We hence parsed through several possible material configurations ranging from concrete shells to brick vaults for building this ‘architectural landscape’.”

“The design team became interested in the material efficiencies of the Catalan tile vault from the 16th century, its use by Spanish architect Guastavino in the early 19th century, and the details used in the work of uruguayan engineer and architect Eladio Dieste. to articulate a pure compression form for the library, sP+a used rhinoVAULT — a form-finding plug-in developed by the block research group at ETH zürich. consequently, the Maya Somaiya Library is the result of lessons learned from different time periods as well as geographic locations.”

A crafty reading railroad, this conveyor system helps bring up books from a series of research stacks and storage spaces hidden beneath Bryant Park, making the volumes available via a system of miniature trains.

This particular branch of the New York Public Library in the Stephen A. Schwarzman Building houses millions of volumes, many of which are stored below the ground but now accessible at speed thanks to this new layer of internal technology.

This book train system looks a bit like a tiny roller coaster and is used to transfer materials seamlessly, quickly and automatically along the vertical-and-horizontal track system, carrying requested books directly to places like the Rose Main Reading Room.

Each cart (of which there are 24) can hold 30 pounds of reading materials and can climb 11 stories within the building to service various floors.

A pivot joint between the book-carrying basket and the main body of the cart allows the former to remain upright without spilling its contents while the latter tilts up to 90 degrees, carrying books straight up between levels.

If you’ve ever gotten bored with the book you’re reading on the beach and wished you could just run into a seaside library for a new one, here’s the building of your dreams: a stunning modern repository of books so close to the sea, it’s practically on the water. Vector Architects positioned this monumental concrete structure right on the edge of China’s Bohai Bay, about three hours from Beijing, with massive glass doors opening the reading space right onto the sand.

Oriented to direct nearly all of its views to the water, the library feels strong and solid, anchored to the sand. Of course, it’s hard not to worry about all of those books being ruined in the event of a severe storm. It’s not clear whether the architects have taken any particular precautions against potential disasters, but it certainly looks like a beautiful place to sit and read, especially when the lower doors are all open to the breezes coming off the water.

Steel roof trusses support the massive canopy roof, which curves down into the wall at the rear of the building. Upper-level benches and tables look out a strip of fixed windows, and a stairway leads to a small rooftop patio. In contrast, a meditation room is  insulated from the rest of the space, the only windows a handful of skylights carefully directing natural light.

The building feels like a real-life version of a series of storm-proof fantasy beach structures by Dionisio Gonzalez – architecture with the heft and wherewithal to stand up to the elements when other buildings would be swept away.

A project in Chicago is turning train cars in the city’s elevated rail network into moving libraries, providing free reads for travelers and commuters using the public transit system.

The Books On the L lending project began as a concept pitched during Chicago Ideas Week and operates with a simple and effective lending policy for this novel type of mobile library: you can read as long as you ride.

The Chicago Transit Authority trains will be populating cars with volumes from hundreds of genres, and could potentially give access to thousands more if they implemented QR codes for ebook reading devices.

The same idea has informally manifested itself in other cities as well, part of a larger Books on the Subway (or Underground) movement that ranges from ‘find a book, leave a book’ ideals to more organized endeavors in places including London, Washington D.C. and New York City. But readers beware: become too engrossed in your borrowed page-turner and you may miss your stop.