Photo taken on Nov. 12, 2019 shows the debris in Pripyat city near the Chernobyl nuclear power plant in Ukraine. The Chernobyl nuclear power plant, some 110 km north of Kiev, witnessed one of the worst nuclear accidents in human history on April 26, 1986. As radiation levels decreased, the 30-square-km area around the plant was officially opened to tourists in 2010. Guided tours to the plant were launched in 2018. (Xinhua/Bai Xueqi)

Photo taken on Nov. 12, 2019 shows the debris in Pripyat city near the Chernobyl nuclear power plant in Ukraine. The Chernobyl nuclear power plant, some 110 km north of Kiev, witnessed one of the worst nuclear accidents in human history on April 26, 1986. As radiation levels decreased, the 30-square-km area around the plant was officially opened to tourists in 2010. Guided tours to the plant were launched in 2018. (Xinhua/Bai Xueqi)

People visit a deserted amusement park near the Chernobyl nuclear power plant in Ukraine, Nov. 12, 2019. The Chernobyl nuclear power plant, some 110 km north of Kiev, witnessed one of the worst nuclear accidents in human history on April 26, 1986. As radiation levels decreased, the 30-square-km area around the plant was officially opened to tourists in 2010. Guided tours to the plant were launched in 2018. (Xinhua/Bai Xueqi)

A ferris wheel is seen near the Chernobyl nuclear power plant in Ukraine, Nov. 12, 2019. The Chernobyl nuclear power plant, some 110 km north of Kiev, witnessed one of the worst nuclear accidents in human history on April 26, 1986. As radiation levels decreased, the 30-square-km area around the plant was officially opened to tourists in 2010. Guided tours to the plant were launched in 2018. (Xinhua/Bai Xueqi)

Photo taken on Nov. 12, 2019 shows the debris in Pripyat city near the Chernobyl nuclear power plant in Ukraine. The Chernobyl nuclear power plant, some 110 km north of Kiev, witnessed one of the worst nuclear accidents in human history on April 26, 1986. As radiation levels decreased, the 30-square-km area around the plant was officially opened to tourists in 2010. Guided tours to the plant were launched in 2018. (Xinhua/Bai Xueqi)

Photo taken on Nov. 12, 2019 shows the debris in Pripyat city near the Chernobyl nuclear power plant in Ukraine. The Chernobyl nuclear power plant, some 110 km north of Kiev, witnessed one of the worst nuclear accidents in human history on April 26, 1986. As radiation levels decreased, the 30-square-km area around the plant was officially opened to tourists in 2010. Guided tours to the plant were launched in 2018. (Xinhua/Bai Xueqi)

People visit a deserted radar station near the Chernobyl nuclear power plant in Ukraine, Nov. 12, 2019. The Chernobyl nuclear power plant, some 110 km north of Kiev, witnessed one of the worst nuclear accidents in human history on April 26, 1986. As radiation levels decreased, the 30-square-km area around the plant was officially opened to tourists in 2010. Guided tours to the plant were launched in 2018. (Xinhua/Bai Xueqi)

Photo taken on Nov. 12, 2019 shows the debris in Pripyat city near the Chernobyl nuclear power plant in Ukraine. The Chernobyl nuclear power plant, some 110 km north of Kiev, witnessed one of the worst nuclear accidents in human history on April 26, 1986. As radiation levels decreased, the 30-square-km area around the plant was officially opened to tourists in 2010. Guided tours to the plant were launched in 2018. (Xinhua/Bai Xueqi)