This undated photo provide by the European Space Agency and captured by ESA astronaut Andre Kuipers, shows the German capital Berlin from the International Space Station, ISS. Seen from above, street lights in the former East Berlin appear slightly more orange; those in the western part of the city are a harsher yellow. ( ESA / AP

In some ways, Berlin is still divided 30 years after the fall of the Berlin Wall.

Seen from space, the city’s lights show a stark contrast, with orange lights in the east and white lights in the west.

One of the reasons for this is that each side of the city still uses different types of lights, light shades, and fittings.

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Thirty years after the fall of the Berlin Wall, Berlin is divided by light.

The contrast is a legacy from the Cold War, when Germany was divided from east to west as tensions mounted between America and the West, against Russia. Berlin was divided down the middle by a brick and wire wall for 10,316 days. When the wall fell, it heralded the end of the Cold War.

East German policemen at the wall along Bernauer Strasse in September 1961. Edwin Reichert/AP

And while Berlin has been a united city for 30 years now, the division can still be seen glowing on clear nights. East Berlin glows orange while to West Berlin glows a bright white.

European Space Agency astronaut Andre Kuipers took the image at the top of this story from the International Space Station.

Netherlands\' astronaut Andre Kuipers Mikhail Metzel / AP

One of the reasons for the light divide is that the light shades and fittings used are different from one side of the city to the other, according to the AP.

Daniela Augenstine, who worked in Berlin’s street furniture department, told The Guardian that the east uses sodium-vapor lamps, which are older and produce a yellower light, while the west uses fluorescent lamps, which producer a brighter, whiter light. The west preferred non-sodium lamps because they were cheaper, easier to maintain, and better for the environment.

According to The Telegraph, another reason for the contrast is that West Berlin has boomed with shopping and commercial districts, compared to East Berlin, and the light reflects the higher levels of activity.

Gas light in Berlin. Aslu / ullstein bild / Getty

Christa Mientus-Schirmer, who worked for the Berlin city government, told The Guardian that although a lot of progress had been made to unify the city after the wall fell, the city government hasn’t had the funding it would have liked to be able to make the two halves of the city equal.

This isn’t the only photo to show Berlin’s night light divide. In 2013, Canadian astronaut Chris Hadfield also took a photo from the ISS when he noticed the difference.

But astronauts might not be able to see the divide for too much longer — Berlin is replacing its gas-powered lights with electrical ones to reduce energy consumption. According to German newspaper Der Tagesspiegel, about 30,000 gas lamps were still in service as of January 2019.