On April 26, Ukraine marks the anniversary of the 1986 Chernobyl accident – the world's worst nuclear disaster. An explosion in a reactor at the Chernobyl Nuclear Power Plant left swathes of Ukraine and neighboring Belarus badly contaminated and led to the creation of a no man's land within a 30-kilometer (19-mile) radius of the station. Ukrainian authorities say the area may not be fit for humans for 24,000 years.

Toys are seen in a kindergarten near the Chernobyl Nuclear Power Plant in the abandoned city of Pripyat, Ukraine, April 12, 2021.

An interior view shows the house in the abandoned village of Zalissya near the Chernobyl Nuclear Power Plant, Ukraine, April 12, 2021.

The coat of arms of the Soviet Union is seen on the roof of a building in the abandoned city of Pripyat near the Chernobyl Nuclear Power Plant, Ukraine, April 12, 2021.

An interior view shows the house in the abandoned village of Zalissya near the Chernobyl Nuclear Power Plant in Ukraine, April 12, 2021.

An elk is seen on a road in the Chernobyl exclusion zone, Ukraine, April 12, 2021.

An employee is reflected in a control centre of the Chernobyl Nuclear Power Plant in Chernobyl, Ukraine, March 25, 2021.

A calendar is seen on the wall in a house in the abandoned village of Zalissya near the Chernobyl Nuclear Power Plant, Ukraine, April 12, 2021.

An employee walks at a control center of the damaged fourth reactor at the Chernobyl Nuclear Power Plant in Chernobyl, Ukraine, March 25, 2021.

An employee is seen in the reactor hall of the stopped third bloc at the Chernobyl Nuclear Power Plant in Chernobyl, Ukraine, March 25, 2021.

A house is seen in the abandoned village of Poliske near the Chernobyl Nuclear Power Plant, Ukraine, April 12, 2021.

An employee is seen in a control center of the stopped third reactor at the Chernobyl Nuclear Power Plant in Chernobyl, Ukraine, March 25, 2021.

An elk is seen in a burnt forest in the Chernobyl zone, Ukraine, April 12, 2021.

Parts of a Soviet-made over-the-horizon (OTH) radar system "Duga" are seen near the Chernobyl Nuclear Power Plant, Ukraine, April 12, 2021.

A vintage doll, which was placed by a visitor, is seen on a bed at a kindergarten near the Chernobyl Nuclear Power Plant in the abandoned city of Pripyat, Ukraine, April 12, 2021.

Remains of burnt houses are seen in the abandoned village of Poliske in the Chernobyl zone, Ukraine, April 12, 2021.

A view shows the abandoned city of Pripyat near the Chernobyl Nuclear Power Plant, Ukraine, April 12, 2021.

A view shows the abandoned city of Pripyat near the Chernobyl Nuclear Power Plant, Ukraine, April 12, 2021.

A child's gas mask is seen in a kindergarten near the Chernobyl Nuclear Power Plant in the abandoned city of Pripyat, Ukraine, April 12, 2021.

An employee walks at a control center of the damaged fourth reactor at the Chernobyl Nuclear Power Plant in Chernobyl, Ukraine, March 25, 2021.

Children's beds are seen in a kindergarten near the Chernobyl Nuclear Power Plant in the abandoned city of Pripyat, Ukraine, April 12, 2021.