Giovanni Battista Piranesi's Prisons of the Imagination aren't exactly begging to have new life breathed into them. The dark, dreamlike images are broadly circulated, widely reproduced and possessed of great visual appeal and narrative implication. Successive generations just naturally find their way through the twisting staircases and cavernous vaults to walk among the ropes and chains and thrill to the smoking braziers, spiked wheels and other instruments of torture.

But an installation that pairs the portfolio of 18th-century etchings with new photos of string-art re-creations of them by contemporary artist Vik Muniz offers a timely reinterpretation of Piranesi's architectural allegories of power. It's on view at the National Academy of Sciences.

Piranesi (1720-78) was in his twenties when he made the first edition of plates for what he would later call his Carceri d'Invenzione. Born a Venetian, with all the love of theatricality that implies, he was a student of stage design as well as architecture. It was amid the ancient ruins of Rome, however, that his imagination found a platform on which to play out its schemes.

As legend has it, the Carceri are the stuff of fever dreams, conceived during a bout of malaria. Regardless of the diagnosis, evidence of a proto-romantic sensibility can be found in the sheer outlandishness of the scale of Piranesi's spaces. Their vastness connotes not so much a sublime terror as the notion of Hell as an enormous bureaucracy.

Underlying the brooding, dizzying grandeur is an Enlightenment-era understanding that for "Abandon All Hope" to be emblazoned above the gates of Hell, somebody had to inscribe it there. The gates themselves needed a designer. Other workers still were required to build them and staff them.

The Brazilian-born, New York-based Muniz is known for photographs of images he makes with quirky, often fugitive substances. He has drawn with dust, chocolate, sugar, fake blood and skywriting smoke. For all the skill in evidence, the work has often seemed gimmicky.

But when he undertook, in 2002, to rework the Carceri, outlining the pictures with straight pins, then winding black thread between them to mimic Piranesi's scratched line, he hit upon a technique that makes us regard the prisons anew. Muniz flattens the spaces -- making them less illusionistic, less theatrical -- at the same time that he re-rationalizes the effort that brought them into being -- both Piranesi's own and that of the imagined powers behind these monuments to state cruelty.

Just as Muniz labored in service to Piranesi, the builders of these grandiose dungeons would have labored in service to their designers. The impetus for anyone in the lower reaches of the chain of command was not simply to avoid the wrath of the higher-ups but to participate in the grand drama of the exercise of power. What Piranesi understood is that to answer the call of the state and to find one's place amid its architecture can be an awesome thing. The Carceri exist at the intersection of personal duty and megalomaniacal fantasy. Their cautionary tales employ for their moral lever not horror but exhilaration.

Canadian Video at Numark Gallery

Numark introduces an annual summer series of video art with two installations that play in the front room and will be visible from the street 24 hours a day.

The first, "La La City" by Allyson Clay, runs for the next two weeks. The artist's camera is aimed from the aerie of a revolving restaurant out at the cityscape of her home town of Vancouver. For about three-quarters of an hour, the platform turns slowly clockwise. Distant mountains and nearer skyscrapers creep by. Smudged windowpanes and the blocky mullions between them pass with comparative speed. Boats and ships sketch wakes on the water.

But before we've completed the circuit, the screen starts to sizzle and jump and the footage reverses. The time that so smoothly, narcotically unfolded is sucked up at the same speed, but with the addition of a disturbing amount of visual noise. (I've since learned there was a problem with the disc I screened. Numark promises that the reversal will be a more placid experience for future viewers.)

Following Clay's piece the last week of the month will be five very short videos by Euan Macdonald, who was originally from Toronto, is now based in Los Angeles and specializes in a kind of wry cosmic slapstick, also of the single-shot variety: a soccer ball drifting in a puddle eclipsing the sun's reflection, two planes flying in such strict formation that the pairing looks like a mirage.

In "Hammock," a figure lounges in profile in a cocoon of striped fabric, at first rocking slowly. But unseen hands are at work, swinging the hammock ever harder, until the figure, at last revealed to be a dummy, is making full circles, its refuge turned into a sickening carnival ride.

The subtler "Interval" pits five lanes of traffic against the swaying shadows of two palm trees on the pavement. As the flow of cars snarls, then unspools again, the idyllic outlines are continually marred, then redrawn. The piece strikes a subtle note of environmental warning, playing into a commentary on the inherent contradictions of California dreamin'.

Giovanni Battista Piranesi and Vik Muniz: Prisons of the Imagination at the National Academy of Sciences, 2101 Constitution Ave. NW, Monday-Friday 9 a.m.-5 p.m., 202-334-2436, to Dec. 31.

Allyson Clay: La La City at Numark Gallery, 625-27 E St. NW, Tuesday-Thursday 11 a.m.-7 p.m., Friday-Saturday 11 a.m.-6 p.m., 202-628-3810, to Aug. 25.

Euan Macdonald: Interval at Numark Gallery, 625-27 E St. NW, Tuesday-Thursday 11 a.m.-7 p.m., Friday-Saturday 11 a.m.-6 p.m., 202-628-3810, Aug. 26 to Sept. 9.

Vik Muniz's "Carceri XI," above, on view at the National Academy of Sciences, and one of the 18th-century "imaginary prisons" by Piranesi that inspired it. A still from one of Euan Macdonald's short videos at Numark Gallery.