If woodblock prints are to be believed, the metropolis was once awash in greens and blues.

Reedy riverbanks, grassy hillocks and marshes draped with willows all feature in "One Hundred Famous Views of Edo," the 19th-century series of woodblock prints of the capital (then called Edo) by master artist Utagawa Hiroshige. Above all are the waterways, wide rivers and narrow canals colored a deep Prussian blue, crisscrossed by gently arching wooden bridges. Boats — cargo boats, piled high with barrels and steered by stooped men in sampans; pleasure boats, their blinds drawn on the courtesans and patrons within — make their way up and down these causeways. One hundred and fifty years ago, Tokyo, at least from the right angles, looked downright romantic.

So the question is: What happened?