![International Space Station](https://static-ssl.businessinsider.com/image/55cbb234dd0895f0048b45a2-925-694/iss.jpg)
NASA
The International Space Station in orbit.
To see it, take a look at these photos that astronauts snapped of the bustling city of Milan below.
Before Milan transitioned to LEDs, in 2012, the lighting levels in the surrounding suburbs were about the same as those of the city center.
But energy savings does not necessarily translate to happy city-dwellers. In a piece in The New York Times, Brooklyn residents complained about the glaring white light creeping into their homes and eyes, causing many restless nights.
LEDs worsen light pollution by giving off more blue and green light than the high-pressure sodium lights they normally replace. And this artificial light pollution washes out the night sky and is linked to many negative consequences. Disrupted night and day cycles can confuse nocturnal animals and alter their hunting interactions, migratory patterns, and internal physiology.
It can also mess with our internal clocks. We produce melatonin at night to help us sleep, which is regulated by light and dark cycles. If we're exposed to light at night, this can suppress melatonin levels, leading to sleep disorders or other problems such as headaches, anxiety, and obesity.