Renzo Piano and Richard Rogers's Centre Georges Pompidou of 1971-1977 - the true prototype of the modern museum as popular architectural spectacle - wound up costing so much more than planned that the French government solved the shortfall by cutting support for several regional museums.

There is no sadder tale in the annals of architecture than the virtual disappearance of the defining architectural form of the Modern Movement - publicly sponsored housing.

Experimental architecture by its very nature is more prone to the depredations of time and natural elements than buildings made from conventional materials through traditional methods. Avant-garde architects often simply do not know how the products of their imagination will perform when implemented, especially if untested components are involved.

There can be little question that the tall building presents one of the most difficult challenges to the architect.

Architecture traditionally has been the slowest of art forms. It was not unusual for great cathedrals to take centuries to complete, with stylistic changes from Romanesque to Gothic or Renaissance to Baroque as common as the addition of chapels or spires. But because the function remained the same, the form could be flexible and its growth organic.

The danger for any artist whose work is both recognizable and critically acclaimed is complacent repetition - the temptation to churn out easily identifiable, eagerly welcomed, and readily salable designs.

When Oscar Niemeyer died on December 5, 2012, ten days before his 105th birthday, he was universally regarded as the very last of the twentieth century's major architectural masters, an astonishing survivor whose most famous accomplishment, Brasilia, was the climactic episode of utopian High Modern urbanism.