Pripyat, Ukraine (CNN) -- There's an eerie stillness about the desolate buildings and empty streets of Pripyat.
From the main square, overgrown with brambles and wild grass, the town looks like an ancient ruin lost in a jungle.
Buildings, windows smashed, stand like monolithic giants peering down. On one, an unlit neon sign saying "restaurant" clings onto a rooftop. From another, a hammer and sickle looms over the scene below.
I can't think of a single place I've visited that feels so utterly abandoned and lost.
The order to evacuate Pripyat came too late. It had been 36 hours since an explosion in Reactor 4 at Chernobyl, on April 26, 1986, had spewed its radioactive debris over the town.
Fearing panic, the then Soviet authorities, under Mikhail Gorbachev, ordered Pripyat's citizens to continue life as normal.
So, as the world's worst nuclear accident wreaked havoc, searing with radiation all in its path, children in this town went to school and sat through lessons. Couples got married.
When the evacuation did get under way, once the scale of disaster could no longer be denied, residents were told they would be back in a few days. They took nothing with them -- just documents, some money and some food for the bus ride.
Even inside the Soviet Union, the disgraceful way the situation was handled by the authorities was severely criticized.
On several occasions since, Gorbachev -- remembered for his perestroika and glasnost reforms -- said he believed Chernobyl was equally responsible for bringing about the collapse of the Soviet Union.
Even 25 years on, the problem of Chernobyl has far from gone away. There is considerable debate over how many people died, and how many are still dying, as a result of the calamity.
The International Atomic Energy Agency and the World Health Organization say 28 emergency workers died of radiation sickness in the immediate aftermath of the disaster. About 20 more who received high doses of radiation died of various causes in the following years, and as many as 4,000 cancer deaths are expected as a result of the disaster, according to those U.N. agencies.
The Chernobyl Union of Ukraine, which supports survivors of the disaster, says 140,000 people who took part in the cleanup have died in the past quarter-century. But it is not clear how many of those fell victim to radiation.
Meanwhile, researchers say that in addition to spikes in certain types of cancers, there is evidence of severe anxiety among survivors. Ukraine's government says an area larger than Switzerland was affected, and a 30-km (19-mile) radius around the plant remains all but uninhabited.
And the impact is unlikely to diminish anytime soon. Nuclear disasters like Chernobyl and Fukushima don't run on a human timeline.
Limited numbers of tourists are allowed into the accident zone for brief visits, despite radiation being well above normal, but scientists say generations may pass before it is entirely safe for people to return.