Seventy years ago, some experts were convinced that nuclear power would change the world for the better. “Here was the power that would do all work…of a veritable Utopia,” the editors of a book on the Atomic Age wrote in 1945.

They also thought it would quickly grow. In the mid-1960s, one estimate predicted that by the year 2000, nuclear power would supply more than half of all the electricity in the U.S. As of 2016, it’s at a little less than 20%; globally, it’s only about 14%.

A new map from Carbon Brief shows the location of every reactor ever built around the world, including the 400 nuclear power stations now in use and others under construction. “Once you see it visually like that, you really get a sense of where the history of nuclear power is, and where it’s future is going to be,” says Simon Evans, policy editor for the U.K.-based Carbon Brief.

Some countries have given up on nuclear power completely, such as Germany, which closed eight reactors after the disaster at Fukushima in 2011 and plans to close the rest by 2022. Lithuania and Italy have shut down their reactors. Sweden’s national power company announced in January that its nuclear plants are losing money, and may shut down for financial reasons.

You really get a sense of where the history of nuclear power is, and where it’s future is going to be.

Part of the reason for slow growth of nuclear is the gigantic cost of building a plant. While technologies like wind and solar keep dropping dramatically in price, nuclear is getting more expensive in most countries. Since the mid-1950s, when the price of both nuclear and solar panels was first published, the cost of nuclear power has gone up three times. Solar, on the other hand, has become 2,500 times cheaper in the same period.

New reactors at Georgia Power’s Vogtle plant were initially estimated to cost $14 billion to build; the latest estimate is $21 billion. The first reactors at the plant, in the 1970s, took a decade longer to build than planned, and cost 10 times more than expected. In France, a new plant is running around six years behind scheduled and likely to cost around $8 billion more than planned.