A hornbill perches on a tree branch in the Leuser National Park in Bakongan, southern Aceh Province, Indonesia, on April 16, 2019. (Photo by AFP)

The pavilion of the Baden-Wuerttemberg federal state is seen behind blooming flowers during the Federal Horticultural Show (Bundesgartenschau) in Heilbronn, southern Germany, on April 16, 2019. (Photo by AFP)

Greenpeace activists demonstrate on Lake Leman against plastic usage in front of Nestle headquarters in Vevey, Switzerland, on April 16, 2019. (Photo by Reuters)

Gulls gather on the shore of Race Point Beach near Provincetown, Massachusetts, the US, on April 15, 2019. (Photo by AFP)

A child swings in a park in front of the European Central Bank (ECB) headquarters and the skyline in Frankfurt am Main, western Germany, on April 16, 2019. (Photo by AFP)

The morning sun rises over a waterlogged maize field in Buzi District, Mozambique, on April 15, 2019. (Photo by AFP)

A commuter walks along Waterloo Bridge, which is being blocked by climate change activists, during the Extinction Rebellion protest in London, Britain, on April 16, 2019. (Photo by Reuters)

White storks are seen inside their nest atop a chimney above the rooftops in Rust, Austria, on April 16, 2019. (Photo by Reuters)

A Buddhist monk offers a watermelon as he prepares to bless the temple’s elephant during a ceremony as part of the Sinhala, Hindu, and Tamil new year celebrations in Colombo, Sri Lanka, on April 17, 2019. (Photo by Reuters)

A man rows a wooden boat to fish in Kuta Fajar River, southern Aceh Province, Indonesia, on April 16, 2019. (Photo by AFP)