Tourists take photographs of sunrise at Phanom Rung, a Hindu Khmer Empire temple complex, during Phanom Rung Historical Park Festival in Buriram Province in the Isan region of Thailand, April 5, 2019. Phanom Rung Historical Park Festival is usually held every first weekend of April to celebrate the unusual phenomenon when the rays of the rising sun shine through all of the Khmer temple's 15 doorways at the same time. This awe-inspiring spectacle takes place four times a year at the Phanomrung Sanctuary and is believed to bring great blessings upon everyone who is there to witness it. (Xinhua/Zhang Keren)

Performers are seen at Phanom Rung, a Hindu Khmer Empire temple complex, during Phanom Rung Historical Park Festival in Buriram Province in the Isan region of Thailand, April 6, 2019. Phanom Rung Historical Park Festival is usually held every first weekend of April to celebrate the unusual phenomenon when the rays of the rising sun shine through all of the Khmer temple's 15 doorways at the same time. This awe-inspiring spectacle takes place four times a year at the Phanomrung Sanctuary and is believed to bring great blessings upon everyone who is there to witness it. (Xinhua/Zhang Keren)

Performers are seen at Phanom Rung, a Hindu Khmer Empire temple complex, during Phanom Rung Historical Park Festival in Buriram Province in the Isan region of Thailand, April 6, 2019. Phanom Rung Historical Park Festival is usually held every first weekend of April to celebrate the unusual phenomenon when the rays of the rising sun shine through all of the Khmer temple's 15 doorways at the same time. This awe-inspiring spectacle takes place four times a year at the Phanomrung Sanctuary and is believed to bring great blessings upon everyone who is there to witness it. (Xinhua/Zhang Keren)

Aerial photo taken on April 6, 2019 shows the Phanom Rung, a Hindu Khmer Empire temple complex in Buriram Province in the Isan region of Thailand. Phanom Rung Historical Park Festival is usually held every first weekend of April to celebrate the unusual phenomenon when the rays of the rising sun shine through all of the Khmer temple's 15 doorways at the same time. This awe-inspiring spectacle takes place four times a year at the Phanomrung Sanctuary and is believed to bring great blessings upon everyone who is there to witness it. (Xinhua/Zhang Keren)

Performers are seen at Phanom Rung, a Hindu Khmer Empire temple complex, during Phanom Rung Historical Park Festival in Buriram Province in the Isan region of Thailand, April 6, 2019. Phanom Rung Historical Park Festival is usually held every first weekend of April to celebrate the unusual phenomenon when the rays of the rising sun shine through all of the Khmer temple's 15 doorways at the same time. This awe-inspiring spectacle takes place four times a year at the Phanomrung Sanctuary and is believed to bring great blessings upon everyone who is there to witness it. (Xinhua/Zhang Keren)

Tourists wait to take photographs of sunrise at Phanom Rung, a Hindu Khmer Empire temple complex, during Phanom Rung Historical Park Festival in Buriram Province in the Isan region of Thailand, April 5, 2019. Phanom Rung Historical Park Festival is usually held every first weekend of April to celebrate the unusual phenomenon when the rays of the rising sun shine through all of the Khmer temple's 15 doorways at the same time. This awe-inspiring spectacle takes place four times a year at the Phanomrung Sanctuary and is believed to bring great blessings upon everyone who is there to witness it. (Xinhua/Zhang Keren)

A performer is seen at Phanom Rung, a Hindu Khmer Empire temple complex, during Phanom Rung Historical Park Festival in Buriram Province in the Isan region of Thailand, April 6, 2019. Phanom Rung Historical Park Festival is usually held every first weekend of April to celebrate the unusual phenomenon when the rays of the rising sun shine through all of the Khmer temple's 15 doorways at the same time. This awe-inspiring spectacle takes place four times a year at the Phanomrung Sanctuary and is believed to bring great blessings upon everyone who is there to witness it. (Xinhua/Zhang Keren)

Performers are seen at Phanom Rung, a Hindu Khmer Empire temple complex, during Phanom Rung Historical Park Festival in Buriram Province in the Isan region of Thailand, April 6, 2019. Phanom Rung Historical Park Festival is usually held every first weekend of April to celebrate the unusual phenomenon when the rays of the rising sun shine through all of the Khmer temple's 15 doorways at the same time. This awe-inspiring spectacle takes place four times a year at the Phanomrung Sanctuary and is believed to bring great blessings upon everyone who is there to witness it. (Xinhua/Zhang Keren)

Performers are seen at Phanom Rung, a Hindu Khmer Empire temple complex, during Phanom Rung Historical Park Festival in Buriram Province in the Isan region of Thailand, April 6, 2019. Phanom Rung Historical Park Festival is usually held every first weekend of April to celebrate the unusual phenomenon when the rays of the rising sun shine through all of the Khmer temple's 15 doorways at the same time. This awe-inspiring spectacle takes place four times a year at the Phanomrung Sanctuary and is believed to bring great blessings upon everyone who is there to witness it. (Xinhua/Zhang Keren)

Performers are seen at Phanom Rung, a Hindu Khmer Empire temple complex, during Phanom Rung Historical Park Festival in Buriram Province in the Isan region of Thailand, April 6, 2019. Phanom Rung Historical Park Festival is usually held every first weekend of April to celebrate the unusual phenomenon when the rays of the rising sun shine through all of the Khmer temple's 15 doorways at the same time. This awe-inspiring spectacle takes place four times a year at the Phanomrung Sanctuary and is believed to bring great blessings upon everyone who is there to witness it. (Xinhua/Zhang Keren)

Tourists take photographs of sunrise at Phanom Rung, a Hindu Khmer Empire temple complex, during Phanom Rung Historical Park Festival in Buriram Province in the Isan region of Thailand, April 5, 2019. Phanom Rung Historical Park Festival is usually held every first weekend of April to celebrate the unusual phenomenon when the rays of the rising sun shine through all of the Khmer temple's 15 doorways at the same time. This awe-inspiring spectacle takes place four times a year at the Phanomrung Sanctuary and is believed to bring great blessings upon everyone who is there to witness it. (Xinhua/Zhang Keren)