Left: The new Timber Gridshell building at the Weald and Downland Museum, Singleton, West Sussex.

Enormous greenhouses, transparent foil walls, rooms suspended in dark voids and towers that rotate. Around the UK giant glass bubbles and buildings in shining armour have been rising from the ground. Buckets of lottery money have been poured into wet mud and from these unpromising sites have sprung some fantastical museum buildings.

New museums have been contracting big name architects to design flagship buildings. These projects have become test-beds for architectural innovation.

Museums have broken free of the white-box neutrality that dominated gallery design through the middle of the twentieth century; we are now being treated to loud and proud architecture.

Glasgow Science Centre is an extraordinary, shiny aardvark of a building, accompanied by a shell-like Imax cinema and a 400-foot revolving tower.

Architect Nicolas Grimshaw has used aluminium cladding for the exterior of the building.

The reflected light off the surrounding water makes an eye-watering sight.

Computer modelling has enabled Norman Foster's Great Court roof design at the British Museum.

The roof is made up of thousands of unique triangular glass panes. It has an undulating doughnut shape and links the roof of the reading room to the cornices of the four interior facades.

The museum's new heart has been immensely popular with visitors, and you can see why. The space has a grand scale, dreamy light quality and an ambience conducive to dazed wandering with eyes turned upward.

The Lowry Centre in Salford Quays, carries all the hallmarks of a 'celebrity museum'. The building demands attention, dominating the industrial landscape around it. Its extravagant geometry makes a statement from a mile away.

It was built to house the City of Salford Lowry Collection and provide a theatre and exhibition space. But the architecture makes an exhibition of itself, an example of 90's millenarianism in museum design.

Another triumph for Nicolas Grimshaw and Partners is the Eden Project in Cornwall. It houses a botanical cornucopia and is the largest greenhouse in the country. It is made up of interconnected geodesic domes and is glazed with inflated foil pillows.

These glazing units are manufactured to offer specific levels of protection from the sun and their negligible weight compared with glass, means the bubble design of the building needs no pillars inside.

The result is a botanical oasis held in a cloudlike capsule. The spider-web structure seems to hold the garden in a delicate force field against the harshness of its quarry-pit surroundings.

Wales has its own answer to high-tech greenhouses.

The National Botanic Garden of Wales is a single glass dome built over a botanic garden.

The garden is sunk into the ground and the gentle rise of the dome echoes the shapes of the Welsh hills which are its setting.

Ecology and architecture are coming together again at the Weald and Downland Open Air Museum. The new Gridshell building is a conservation centre built using ground-breaking structural carpentry techniques.

From the outside it looks like the upturned hull of a sailing ship, except that it swirls and bulges in a rather un-aqua-dynamic way. Inside the domed structure resembles a wooden Eden.

Another example of single form architecture is the American Air Museum in Britain at the Imperial War Museum, Duxford.

The Duxford airstrip was the base for the American 8th and 9th Air Forces during the Second World War. Norman Foster has designed an unforgettable building to house these historic machines.

The structure is based on a single geometrical form, a section or a sphere, chosen to cope with the problem of housing an original B52 Bomber, which takes a large portion of the floor plan.

What might previously have been a 'museum of science', now is more likely to be a 'science centre'. Several examples of this have sprung up recently.

Just outside Leicester, The National Space Science Centre looks like a spaceship ready to launch because, surprise, surprise, there is a rocket inside.

Its single curve shape is not unlike the Glasgow Science Centre tipped up on its end, except for one thing; this building is glazed with a plastic membrane. As with the Eden Project, this allows huge spans of transparent walling with minimal structural support.

From the outside it looks like a clear cocoon with a rocket ready to break out. From the inside what you get is a light-filled tower and a sense of airy space. This is a centre of science rather than a museum, the building incorporates activities for children aimed at learning about space, the universe and everything.

Magna, an interactive science centre in Rotherham has been built in an old steelworks.

Its two enormous bays are now home to four pavilions, earth, air, fire, and water, suspended in the voids of these monumental spaces.

The effect is a visual extravaganza, the building has supplied the backdrop to a dramatic interior space aimed at inspiring wonder in its audience.

Another industrial space adapted into a cultural one is of course Herzog and de Meuron's Tate Modern. Created out of the shell of Bankside power station, it houses the 20th century part of the Tate collection.

It's main selling point is the gargantuan turbine hall that has been maintained as an interior void, a massive statement in space about the importance of art in the heart of the city.

'Explore at Bristol' was a Great Western Railway goods shed. It has been given a glass face-lift, extending the frontage of the site and providing a covered foyer area.

Exhibition space and roof terraces have been constructed in, on and around the old building. Explore is a part of a riverside development in the centre of the city called At Bristol; a three venue complex with Imax cinema and education centre.

The architecture of Explore has merged not only with the old building but also with its new exhibits. A ten-meter transparent tower is filled with balls containing eutetic salts that passively regulate the temperature of the building. This doubles up as an exhibit, and a giant feature of the lobby space.

In London there have been some inspiring modern additions to existing museum buildings. Having managed to escape the clutching claws of conservative town planners, these museums have brought something new and exciting to recognised institutions that could so easily have been scared of marring traditional architecture.

Rick Mather has designed an extension to what has been described as the 'the most beautiful art gallery in England'. Quite a daunting task for any architect, but Mather has received several architectural awards for his extension to the Dulwich Picture Gallery.

This project comprises the restoration of the original 1811 building by Sir John Soane, and the addition of a new gallery and cloister.

The gallery has been fabricated in materials matching the original architecture and the cloister linking old to new is made from glass and bronze. The attention to detail, material and environment make this an aesthetic feast.

An extension to the existing Geffrye Museum has enabled the collection to be arranged in a linear chronology displaying the range from 18th to 21st century domestic interiors. The windowless brick curve that is the new addition connects the two almshouses and provides a fluid space between the two rigid blocks.

At last London has done something to rival the public spaces of Paris. A series of developments at Somerset House have created a newly accessible public space and opened up the courtyard as a place of entertainment.

The route from the river, through the great arch, into the courtyard and out to the Strand is now an enjoyable experience in its own right.

Rows of fountains set into the cobbles give a lively focus point around which to enjoy the newly scrubbed architecture of the late 18th century building. During the colder seasons an ice-skating rink appears in the courtyard and immediately transports you from Paris to Stockholm.

So what of the future? Will these modern monuments age gracefully or will they look tired in fifteen years time? If so what will replace them?

Perhaps a glimpse of what is in store for museums of the future would be the much-debated plans for an extension at the V&A. Should the traditional façade be maintained as it was intended, or should we embrace the radical proposal of Daniel Libeskind? A spiral of one continuous wall, clad in white tiles and looking like a balled up sheet of paper stuffed between the V&A's flanks.

Libeskind is just the sort of architect that has been coming to prominence in the museum building world. In America and Europe new museums are stretching architectural rules to breaking-point, and whatever the future is, there seems no doubt museums will be exciting and progressive, if not always received with unanimous good will.