Tulips are seen at the central station in Amsterdam, the Netherlands, April 8, 2020. Amsterdam's Tulip Festival 2020 brings tulips into streets throughout the whole month of April. Due to the coronavirus epidemic, some tulip locations are closed this year. (Photo by Sylvia Lederer/Xinhua)

Flowerpots with tulips are seen on the street in Amsterdam, the Netherlands, April 8, 2020. Amsterdam's Tulip Festival 2020 brings tulips into streets throughout the whole month of April. Due to the coronavirus epidemic, some tulip locations are closed this year. (Photo by Sylvia Lederer/Xinhua)

Flowerpots with tulips are seen at the central station in Amsterdam, the Netherlands, April 8, 2020. Amsterdam's Tulip Festival 2020 brings tulips into streets throughout the whole month of April. Due to the coronavirus epidemic, some tulip locations are closed this year. (Photo by Sylvia Lederer/Xinhua)

A flowerpot with tulips is seen in Amsterdam, the Netherlands, April 8, 2020. Amsterdam's Tulip Festival 2020 brings tulips into streets throughout the whole month of April. Due to the coronavirus epidemic, some tulip locations are closed this year. (Photo by Sylvia Lederer/Xinhua)

Tulips are seen in front of the NEMO science museum in Amsterdam, the Netherlands, April 8, 2020. Amsterdam's Tulip Festival 2020 brings tulips into streets throughout the whole month of April. Due to the coronavirus epidemic, some tulip locations are closed this year. (Photo by Sylvia Lederer/Xinhua)