On an information board at Niagara Falls, we discover a historical photograph.

At first glance, it looks like a failed photomontage. Factory buildings and chimneys stand above the cliff edge. Thick pipes run down the slope. Between the buildings, water shoots out of the gorge wall. The names of two companies can be read on their façades: “Pittsburgh Reduction Company” and “Cliff Paper Company”.

It looks as though someone has pasted an industrial landscape in front of Niagara Falls. But nobody has.

The photograph shows the American side of the Niagara Gorge, a little downstream from the falls themselves. Mills and factories were harnessing the enormous power of the water there early on. Electricity came later. In 1895, the Pittsburgh Reduction Company, which would eventually become Alcoa, built an aluminium plant in Niagara Falls. The new metal needed a great deal of electricity, and there was plenty here.

From today’s perspective, a question presses itself upon us: how could anyone build over one of the world’s most spectacular landscapes like this?

The answer is probably soberingly simple: because people saw it differently then. Niagara Falls was already a tourist attraction. But it was also an enormous power source, running constantly. Water fell here in unimaginable quantities. It made sense to use that energy. And if doing so required factories, canals and pipes right beside the gorge, then factories, canals and pipes were built right beside the gorge.

A practical source of energy, with a beautiful view included.

The historical photograph is unsettling above all because we know Niagara Falls differently today. On the American side, paths lead through a green park. Views of rapids and waterfalls open between the trees. The industrial structures in the photograph have disappeared. Standing there today, you need to know they once existed even to imagine them.

This did not happen by chance. The “Free Niagara” movement emerged as early as the nineteenth century. Its supporters included prominent writers and scientists. They opposed private businesses, fences and commercial attractions controlling access to the landscape and obstructing the view. The Niagara Reservation was established in 1885. Buildings were removed, sightlines reopened and the riverside landscape reshaped.

That by no means ended the industrialisation of the Niagara region. On the contrary: the available hydropower made it an important centre for electricity, metallurgy, chemicals and paper production. The falls were not detached from the technological world. Their water is still regulated and diverted to generate electricity today.

The landscape we see, then, is not untouched nature. It is also the result of a decision about which traces of use should remain visible and which should not. That is precisely why I find the old photograph optimistic.

First, it shows how thoroughly people can change a landscape. You can run pipes over a cliff edge, put factories beside a gorge and make waterfalls disappear between industrial buildings. Once you get used to it, presumably even that seems normal.

But indirectly, the photograph shows something else too: it does not have to stay that way. You can give a landscape back at least part of what you have taken from it. This does not happen by itself. It requires political will, money, planning and a great deal of time. And the result is rarely a return to an original state. Today’s Niagara Falls is still regulated, developed for tourism and surrounded by cities.

But the historical photograph proves that “already destroyed” need not mean “lost for ever”.

People can ruin a magnificent landscape with remarkable reliability. Later, though, they can also go to remarkable lengths to restore it.