An archeologist using a torch inspects the world's oldest limestone cave painting, thought to be dated to at least 45,500 years ago, which is decaying at a rapid pace due to climate change, in Maros regency, South Sulawesi province, Indonesia, May 27, 2021. Picture taken May 27, 2021. REUTERS/Abdul Rahman Muchtar

Archeologists gather while inspecting the world's oldest limestone cave painting, thought to be dated to at least 45,500 years ago, which is decaying at a rapid pace due to climate change, in Maros regency, South Sulawesi province, Indonesia, May 27, 2021. Picture taken May 27, 2021. REUTERS/Abdul Rahman Muchtar

Emmanuel Ndiema, head of archaeology at the National Museums of Kenya, talks to Reuters at a vault containing remains of a child buried around 78,000 years ago in Panga ya Saidi cave near Kenya's coast, at the National Museum of Kenya, in Nairobi, Kenya, May 12, 2021. Picture taken May 12, 2021. REUTERS/Baz Ratner

An employee displays remains of a child buried around 78,000 years ago in Panga ya Saidi cave near Kenya's coast, at the National Museum of Kenya, in Nairobi, Kenya, May 12, 2021. Picture taken May 12, 2021. REUTERS/Baz Ratner

Remains of a child buried around 78,000 years ago in Panga ya Saidi cave near Kenya's coast are shown at the National Museum of Kenya, in Nairobi, Kenya, May 12, 2021. Picture taken May 12, 2021. REUTERS/Baz Ratner

Emmanuel Ndiema, head of Archaeology at the National museums of Kenya holds boxes containing remains of a child buried around 78,000 years ago in Panga ya Saidi cave near Kenya's coast, at a vault in the National Museum of Kenya, in Nairobi, Kenya, May 12, 2021. Picture taken May 12, 2021. REUTERS/Baz Ratner

An employee holds a box containing remains of a child buried around 78,000 years ago in Panga ya Saidi cave near Kenya's coast, at a vault in the National Museum of Kenya, in Nairobi, Kenya, May 12, 2021. Picture taken May 12, 2021. REUTERS/Baz Ratner

Remains of a child buried around 78,000 years ago in Panga ya Saidi cave near Kenya's coast are seen at the National Museum of Kenya, in Nairobi, Kenya, May 12, 2021. Picture taken May 12, 2021. REUTERS/Baz Ratner

Roses are placed next to a grave on Mother's Day at Cave Hill Cemetery in Louisville, Kentucky, U.S., May 9, 2021. REUTERS/Amira Karaoud

People stand next to a grave on Mother's Day at Cave Hill Cemetery in Louisville, Kentucky, U.S., May 9, 2021. REUTERS/Amira Karaoud

A funeral wreath is seen next to a grave on Mother's Day at Cave Hill Cemetery, in Louisville, Kentucky, U.S. May 9, 2021. REUTERS/Amira Karaoud

A man stands next to a grave on Mother's Day at Cave Hill Cemetery, in Louisville, Kentucky, U.S. May 9, 2021. REUTERS/Amira Karaoud

Roses bouquets are placed next to graves on Mother's Day at Cave Hill Cemetery, in Louisville, Kentucky, U.S. May 9, 2021. REUTERS/Amira Karaoud

Mother's Day teddy bear is placed next to a grave at Cave Hill Cemetery Louisville, Kentucky, U.S. May 9, 2021. REUTERS/Amira Karaoud

A boat is seen through the small entrance of the Blue Grotto, one of the glamorous island of Capri's main tourist attractions that would have around 20-25 boats of people inside the cave during the summer season, but is instead empty and closed while the island awaits the return of tourists and the summer season despite the coronavirus disease (COVID-19), in Capri, Italy, April 28, 2021. Picture taken April 28, 2021. REUTERS/Yara Nardi

A general view of the Blue Grotto, one of the glamorous island of Capri's main tourist attractions that would have around 20-25 boats of people inside the cave during the summer season, but is instead empty and closed while the island awaits the return of tourists and the summer season despite the coronavirus disease (COVID-19), in Capri, Italy, April 28, 2021. Picture taken April 28, 2021. REUTERS/Yara Nardi

Vincenzo Iaccarino, 57, rows a boat inside the Blue Grotto, one of the glamorous island of Capri's main tourist attractions that would have around 20-25 boats of people inside the cave during the summer season, but is instead empty and closed while the island awaits the return of tourists and the summer season despite the coronavirus disease (COVID-19), in Capri, Italy, April 28, 2021. Picture taken April 28, 2021. REUTERS/Yara Nardi

Vincenzo Iaccarino, 57, rows a boat inside the Blue Grotto, one of the glamorous island of Capri's main tourist attractions that would have around 20-25 boats of people inside the cave during the summer season, but is instead empty and closed while the island awaits the return of tourists and the summer season despite the coronavirus disease (COVID-19), in Capri, Italy, April 28, 2021. Picture taken April 28, 2021. REUTERS/Yara Nardi

Vincenzo Iaccarino, 57, rows a boat inside the Blue Grotto, one of the glamorous island of Capri's main tourist attractions that would have around 20-25 boats of people inside the cave during the summer season, but is instead empty and closed while the island awaits the return of tourists and the summer season despite the coronavirus disease (COVID-19), in Capri, Italy, April 28, 2021. Picture taken April 28, 2021. REUTERS/Yara Nardi

A general view of the Blue Grotto, one of the glamorous island of Capri's main tourist attractions that would have around 20-25 boats of people inside the cave during the summer season, but is instead empty and closed while the island awaits the return of tourists and the summer season despite the coronavirus disease (COVID-19), in Capri, Italy, April 28, 2021. Picture taken April 28, 2021. REUTERS/Yara Nardi

A general view of the Blue Grotto, one of the glamorous island of Capri's main tourist attractions that would have around 20-25 boats of people inside the cave during the summer season, but is instead empty and closed while the island awaits the return of tourists and the summer season despite the coronavirus disease (COVID-19), in Capri, Italy, April 28, 2021. Picture taken April 28, 2021. REUTERS/Yara Nardi

Vincenzo Iaccarino, 57, enters by boat through a small entrance into the Blue Grotto, one of the glamorous island of Capri's main tourist attractions that would have around 20-25 boats of people inside the cave during the summer season, but is instead empty and closed while the island awaits the return of tourists and the summer season despite the coronavirus disease (COVID-19), in Capri, Italy, April 28, 2021. Picture taken April 28, 2021. REUTERS/Yara Nardi

Vincenzo Iaccarino, 57, enters by boat through a small entrance into the Blue Grotto, one of the glamorous island of Capri's main tourist attractions that would have around 20-25 boats of people inside the cave during the summer season, but is instead empty and closed while the island awaits the return of tourists and the summer season despite the coronavirus disease (COVID-19), in Capri, Italy, April 28, 2021. Picture taken April 28, 2021. REUTERS/Yara Nardi

Mine workers walk 6780 ft (2066 m) underground in the Resolution Copper exploratory mine shaft 10 in Superior, Arizona, U.S., March 30, 2021. Picture taken March 30, 2021. REUTERS/Caitlin O'Hara TPX IMAGES OF THE DAY

Fourteen-year-old Adan Muez is helped to sit up in his bed at Adigrat General Hospital in the town of Adigrat, Tigray region, Ethiopia, March 18, 2021. Adan used to be "strong as a lion" before he spent months hiding in a cave in Ethiopia's northern region of Tigray, his uncle said. "We were hiding and living in a cave for more than three months because of the war. We were only eating roasted barley," said Tadesse Aregawi by his nephew's bed, the boy labouring to breath beside him. On May 4, 2021, Adan was referred to Ayder University hospital in Tigray's capital of Mekelle. Adigrat hospital had run out of the fortified milk and medication they were using to treat him. But Ayder hospital had no record of the boy's admission and Reuters has been unable to locate the family. Picture taken March 18, 2021. REUTERS/Baz Ratner

Fourteen-year-old Adan Muez is helped to sit up in his bed at Adigrat General Hospital in the town of Adigrat, Tigray region, Ethiopia, March 18, 2021. Adan used to be "strong as a lion" before he spent months hiding in a cave in Ethiopia's northern region of Tigray, his uncle said. "We were hiding and living in a cave for more than three months because of the war. We were only eating roasted barley," said Tadesse Aregawi by his nephew's bed, the boy labouring to breath beside him. On May 4, 2021, Adan was referred to Ayder University hospital in Tigray's capital of Mekelle. Adigrat hospital had run out of the fortified milk and medication they were using to treat him. But Ayder hospital had no record of the boy's admission and Reuters has been unable to locate the family. Picture taken March 18, 2021. REUTERS/Baz Ratner

Fourteen-year-old Adan Muez lies in a bed at Adigrat General Hospital in the town of Adigrat, Tigray region, Ethiopia, March 18, 2021. Adan used to be "strong as a lion" before he spent months hiding in a cave in Ethiopia's northern region of Tigray, his uncle said. "We were hiding and living in a cave for more than three months because of the war. We were only eating roasted barley," said Tadesse Aregawi by his nephew’s bed, the boy labouring to breath beside him. On May 4, 2021, Adan was referred to Ayder University hospital in Tigray's capital of Mekelle. Adigrat hospital had run out of the fortified milk and medication they were using to treat him. But Ayder hospital had no record of the boy's admission and Reuters has been unable to locate the family. Picture taken March 18, 2021. REUTERS/Baz Ratner

Fourteen-year-old Adan Muez is helped to sit up in his bed at Adigrat General Hospital in the town of Adigrat, Tigray region, Ethiopia, March 18, 2021. Adan used to be "strong as a lion" before he spent months hiding in a cave in Ethiopia’s northern region of Tigray, his uncle said. "We were hiding and living in a cave for more than three months because of the war. We were only eating roasted barley," said Tadesse Aregawi by his nephew's bed, the boy labouring to breath beside him. On May 4, 2021, Adan was referred to Ayder University hospital in Tigray's capital of Mekelle. Adigrat hospital had run out of the fortified milk and medication they were using to treat him. But Ayder hospital had no record of the boy's admission and Reuters has been unable to locate the family. Picture taken March 18, 2021. REUTERS/Baz Ratner

People visit the Gutman's cave, the largest in the Baltic countries, which is illuminated in green during Ireland's annual Global Greening initiative to mark St. Patrick's Day in Sigulda, Latvia March 16, 2021. REUTERS/Ints Kalnins

People visit the Gutman's cave, the largest in the Baltic countries, which is illuminated in green during Ireland's annual Global Greening initiative to mark St. Patrick's Day in Sigulda, Latvia March 16, 2021. REUTERS/Ints Kalnins

People visit the Gutman's cave, the largest in the Baltic countries, which is illuminated in green during Ireland's annual Global Greening initiative to mark St. Patrick's Day in Sigulda, Latvia March 16, 2021. REUTERS/Ints Kalnins

An ancient artefact, part of various artefacts recently discovered in the Judean Desert caves along with scroll fragments of an ancient biblical texts, is seen during an unveiling event for media at Israel Antiquities Authority laboratories in Jerusalem March 16, 2021. REUTERS/Ammar Awad

An ancient complete basket, part of various artefacts recently discovered in the Judean Desert caves along with scroll fragments of an ancient biblical texts, is seen during an unveiling event for media at Israel Antiquities Authority laboratories in Jerusalem March 16, 2021. REUTERS/Ammar Awad

An employee holds ancient arrow and spear heads, part of various artefacts recently discovered in the Judean Desert caves along with scroll fragments of an ancient biblical texts, during an unveiling event for media at Israel Antiquities Authority laboratories in Jerusalem March 16, 2021. REUTERS/Ammar Awad TPX IMAGES OF THE DAY

An employee holds ancient coins, part of various artefacts recently discovered in the Judean Desert caves along with scroll fragments of an ancient biblical texts, during an unveiling event for media at Israel Antiquities Authority laboratories in Jerusalem March 16, 2021. REUTERS/Ammar Awad

An ancient comb, part of various artefacts recently discovered in the Judean Desert caves along with scroll fragments of an ancient biblical texts, is seen during an unveiling event for media at Israel Antiquities Authority laboratories in Jerusalem March 16, 2021. REUTERS/Ammar Awad

Woven fabric, part of various ancient artefacts recently discovered in the Judean Desert caves, along with scroll fragments of an ancient biblical texts, is seen during an unveiling event for media at Israel Antiquities Authority laboratories in Jerusalem March 16, 2021. REUTERS/Ammar Awad

An employee holds an ancient coin, part of various artefacts recently discovered in the Judean Desert caves along with scroll fragments of an ancient biblical texts, during an unveiling event for media at Israel Antiquities Authority laboratories in Jerusalem March 16, 2021. REUTERS/Ammar Awad

Ancient coins, part of various artefacts recently discovered in the Judean Desert caves along with scroll fragments of an ancient biblical texts, are seen during an unveiling event for media at Israel Antiquities Authority laboratories in Jerusalem March 16, 2021. REUTERS/Ammar Awad

A tourist visits the Oktyabrskaya cave of the Bogdanovich glacier located in the Tian Shan mountain range near Almaty, Kazakhstan February 20, 2021. Picture taken February 20, 2021. REUTERS/Pavel Mikheyev TPX IMAGES OF THE DAY

Tourists visit the Oktyabrskaya cave of the Bogdanovich glacier located in the Tian Shan mountain range near Almaty, Kazakhstan February 20, 2021. Picture taken February 20, 2021. REUTERS/Pavel Mikheyev

A tourist visits the Oktyabrskaya cave of the Bogdanovich glacier located in the Tian Shan mountain range near Almaty, Kazakhstan February 20, 2021. Picture taken February 20, 2021. REUTERS/Pavel Mikheyev

A tourist visits the Oktyabrskaya cave of the Bogdanovich glacier located in the Tian Shan mountain range near Almaty, Kazakhstan February 20, 2021. Picture taken February 20, 2021. REUTERS/Pavel Mikheyev

A tourist visits the Oktyabrskaya cave of the Bogdanovich glacier located in the Tian Shan mountain range near Almaty, Kazakhstan February 20, 2021. Picture taken February 20, 2021. REUTERS/Pavel Mikheyev

A Palestinian woman prepares bread for baking in a hillside cave amid Palestinian worries about Israeli settler incursions into the property, near Hebron, in the Israeli-occupied West Bank, January 28, 2021. Picture taken January 28, 2021. REUTERS/Mussa Qawasma

A Palestinian woman washes utensils outside a hillside cave amid Palestinian worries about Israeli settler incursions into the property, near Hebron, in the Israeli-occupied West Bank, January 28, 2021. Picture taken January 28, 2021. REUTERS/Mussa Qawasma

A Palestinian woman prepares food in a hillside cave amid Palestinian worries about Israeli settler incursions into the property, near Hebron, in the Israeli-occupied West Bank, January 28, 2021. Picture taken January 28, 2021. REUTERS/Mussa Qawasma

A Palestinian woman walks towards a cave amid Palestinian worries about Israeli settler incursions into the property, near Hebron, in the Israeli-occupied West Bank, January 28, 2021. Picture taken January 28, 2021. REUTERS/Mussa Qawasma

A Palestinian woman washes utensils outside a hillside cave amid Palestinian worries about Israeli settler incursions into the property, near Hebron, in the Israeli-occupied West Bank, January 28, 2021. Picture taken January 28, 2021. REUTERS/Mussa Qawasma

Palestinian man Barakat Mour sits in a hillside cave with his brother amid Palestinian worries about Israeli settler incursions into the property, in Masafer Yatta near Hebron, in the Israeli-occupied West Bank, January 28, 2021. Picture taken January 28, 2021. REUTERS/Mussa Qawasma

A Palestinian woman enters a hillside cave amid Palestinian worries about Israeli settler incursions into the property, near Hebron, in the Israeli-occupied West Bank, January 28, 2021. Picture taken January 28, 2021. REUTERS/Mussa Qawasma

Members of the Palestinian family Mour sleep in a hillside cave amid Palestinian worries about Israeli settler incursions into the property, near Hebron, in the Israeli-occupied West Bank, January 28, 2021. Picture taken January 28, 2021. REUTERS/Mussa Qawasma

Palestinian children use a mobile phone inside their family's hillside cave amid Palestinian worries about Israeli settler incursions into the property, near Hebron, in the Israeli-occupied West Bank, January 28, 2021. Picture taken January 28, 2021. REUTERS/Mussa Qawasma

Alexa Cave sits during the viewing of her brother Dustin Higgs, the 13th and final prisoner executed by former U.S. President Donald Trump’s administration, with family members at the Darrow Joseph funeral home in Poughkeepsie, New York, U.S., January 29, 2021. REUTERS/Shannon Stapleton

Alexa Cave grieves for her brother Dustin Higgs, the 13th and final prisoner executed by former U.S. President Donald Trump’s administration, with family members at his graveside in Poughkeepsie, New York, U.S., January 29, 2021. REUTERS/Shannon Stapleton

Alexa Cave grieves for her brother Dustin Higgs, the 13th and final prisoner executed by former U.S. President Donald Trump’s administration, with family members leaving his graveside in Poughkeepsie, New York, U.S., January 29, 2021. REUTERS/Shannon Stapleton

Workers wearing protective suits bury a victim of the coronavirus disease (COVID-19) at a cemetery, in Batu Caves, Malaysia January 27, 2021. REUTERS/Lim Huey Teng

Workers wearing protective suits bury a victim of the coronavirus disease (COVID-19) at a cemetery, in Batu Caves, Malaysia January 27, 2021. REUTERS/Lim Huey Teng

Workers wearing protective suits bury a victim of the coronavirus disease (COVID-19) at a cemetery, in Batu Caves, Malaysia January 27, 2021. REUTERS/Lim Huey Teng

Workers wearing protective suits disinfect themselves after burying a victim of the coronavirus disease (COVID-19) at a cemetery, in Batu Caves, Malaysia January 27, 2021. REUTERS/Lim Huey Teng