All this commercial activity, suddenly developed by turning the capital of the world into productive channels, found the cities of Europe ill adapted to meet the changed conditions. The great towns, Paris excepted, were still in the swaddling-clothes of the Middle Ages; they were walled towns with narrow, tortuous streets, picturesque indeed, but absolutely unfitted for commerce or manufactures according to the modern scale. All the conditions, therefore, made imperative the transformation of the old portions of cities to meet modern demands for circulation, and the extension of their borders to provide for the constant increase in population. Everywhere throughout Europe the design of the cosmopolitan city as planned by the architects of Louis XIV. became the model; everywhere the work of Haussmann in opening congested regions of old cities by means of straight thoroughfares found imitators. Vienna with its Ringstrasse followed the example of Paris as expressed in the boulevards of Colbert; in each case the old fortifications were cleared away to make park-like thoroughfares. The heart of old London was transformed by cutting new streets; Brussels was divided by boulevards. In Italy, Rome, Florence, and Milan, each carried out extensive schemes of improvement based on French models. [Illustration: XXI. LONDON. PLAN OF ALDWYCH AND KINGSWAY CONNECTING HOLBORN AND THE STRAND] With the Germans the cutting through of new streets was undertaken for the twofold reason of facilitating traffic and of admitting light and air into a too congested and unwholesome city quarter. In Frankfort-on-the-Main, in Hamburg, in Berlin, and in Dresden it became necessary to abolish with firm hand evil conditions that had become intolerable, no matter at what sacrifice of buildings enveloped with historical associations. But the Germans have come to modify the French theory of the unconditional superiority of the rectilinear avenue; and now they seek to maintain the essential character of the city, as in the case of Darmstadt, by admitting strong curves, and, wherever desirable, by narrowing or widening the thoroughfare, making compensations by creating open spaces. They have found, also, that a too extensive clearing away of the old buildings which cluster about a great minster or cathedral results in an enhancement of effectiveness only at a sacrifice of scale and a loss of picturesqueness. As a consequence, the Germans have sought a golden mean by creating about a monumental structure free room for the beholder to see the essential parts of the building from a sufficiently remote point of view, while leaving undisturbed single structures small in scale, in order that the main building may appear to have grown out of its surroundings.[6] [Illustration: XXII. LONDON TRAFFIC COMMISSION’S PLAN FOR NEW THOROUGHFARES TO OVERCOME CONGESTION, 1907. Revised by Paul Waterhouse, F. R. I. B. A.]