Architects like to build with wood, masonry, concrete and steel, but most really love glass. They love its diaphanous transparency, its paradoxical combination of strength and fragility, and its unique aesthetic and functional attributes — admitting daylight, visually linking inside and outside spaces, making small spaces feel bigger.

As in other cities, Washington buildings covered primarily in glass have proliferated, especially office buildings. Some designs seem to respond to no particular environmental necessity or site condition, appearing instead to be mostly a manifestation of the architect’s love affair with glass.

But some all-glass buildings make great sense. An outstanding example is the Union Station Bikestation, a small pavilion located on the plaza on the west side of Union Station, a few steps from the Union Station Metro entrance. The Washington office of KGP Design Studio designed the 1,700 square-foot Bikestation for parking, storing, renting and repairing bicycles, as well as for selling bicycle accessories. An adjunct to the capital’s transportation system, the pavilion serves local workers, bikers and tourists.

The Bikestation’s convexly curved volume, lens-shaped in plan, is readily discernible. It suggests a form derived from nature, perhaps inspired by the geometry of an insect body or marine crustacean. Its visible structural skeleton of arched steel tubes, stainless steel tie rods and spider-shaped glass panel supports contribute to this perception.

Yet a different perception and analogy are in play. Clad entirely with transparent glass and anchored at its two end points by concrete buttresses, the pavilion’s structure — think of tie rods as spokes —“echoes a bicycle wheel’s elegance and efficiency,” according to the Bikestation brochure.

Beyond providing transparency and weather protection, the glass skin includes automated vents that open and close to induce natural air flow and exhaust warm air, supplementing mechanical cooling and ventilation. A pattern of narrow, horizontal stripes, composed of ceramic “frit” fused to the surface of the low-emissivity glass, reduces solar heat gain while allowing views in and out. At night, the pavilion glows like a luminescent jewel.

The Bikestation’s unusual shape, high-tech structural skeleton and all-glass skin are appropriate for the building’s function. They also provide a dynamic aesthetic counterpoint to the neoclassically styled, monumentally scaled institutional buildings that surround the pavilion.

We think of glass as a modern architectural material, but it’s been around since ancient Rome. Window glass reached its pre-modern artistic height in the stained glass windows of European Gothic cathedrals. In the 19th century, the Industrial Revolution led to new glass-making techniques and mass production that enabled the use of glass for more than just window panes.

Arguably the most sensational, technologically ground-breaking 19th century glass edifice was engineer Joseph Paxton’s Crystal Palace, an immense, vaulted pavilion 1,850 feet long, 128 feet high and encompassing almost 1 million square feet. With a pre-fabricated cast-iron structural skeleton and all-glass skin, the Crystal Palace was erected in London’s Hyde Park for the Great Exposition of 1851, after which it was disassembled and rebuilt on another site. Regrettably, it burned down in the 1930s.

In 1921, German architect Mies van der Rohe designed an all-glass skyscraper which, while never built, foreshadowed the countless glass-clad skyscrapers that would rise in cities around the world during the 20th century.

As demonstrated by KGP’s Bikestation, iconic architecture in glass doesn’t have to be high or huge in scale. One of architect Philip Johnson’s most notable works is his one-story, modestly-sized but very elegant all-glass house built in 1949 in New Canaan, Conn. A simple rectangle in plan and elevation, Johnson’s transparent, minimalist house is enclosed entirely with large glass panels. Only the interior bathroom is opaquely clad. On a large landscaped parcel with no close neighbors, Johnson’s house needed no curtains or shades.

Of course, Johnson was not averse to grandiosity. Perhaps inspired by Paxton’s Crystal Palace, Johnson designed the daylight-filled Crystal Cathedral in Orange County, Calif., completed in 1980. An enormous religious sanctuary seating more than 2,700 worshipers, the Crystal Cathedral’s skin was constructed using 10,000 rectangular panes of glass. Today the building is for sale.

A few years ago, the city of Seattle built a new library with a faceted skin composed only of diamond-shaped glass panels, some clear and some opaque. Designed by Dutch architect Rem Koolhaas, the 11-story library is an abstractly shaped, dramatically angular form covering an entire downtown block. Equally dramatic interior spaces are brightly suffused with daylight, even when it rains, a benefit much appreciated in Seattle.

State-of-the-art curtain wall technology allows architects to wrap buildings with increasingly large sheets of glass, to support glass with ever-thinner framing elements and hardware and to construct ever more complex glass skins. Glass can be manufactured using permanent coatings, surface etching and laminations to create artistic patterns, modulate light transmission, block solar radiation or sustain high impact forces.

Energy-efficient glass, resisting conduction and radiation of heat, has made all-glass facades increasingly feasible. And by optimizing the amount of daylight reaching building interiors, a glass skin significantly reduces electric lighting needs and energy consumption. Now viewed as a relatively “green” building material, today’s glass is indeed not your father’s glass.

Roger K. Lewis is a practicing architect and a professor emeritus of architecture at the University of Maryland.