A staff member puts a one-way sign at the reopened VanDusen Botanical Garden in Vancouver, Canada, on May 1, 2020. Vancouver started on Friday to gradually reopen public recreation facilities with safety measures amid COVID-9 pandemic. (Photo by Liang Sen/Xinhua)

A visitor follows the sign instruction by waiting the bridge to be cleared before crossing it at the reopened VanDusen Botanical Garden in Vancouver, Canada, on May 1, 2020. Vancouver started on Friday to gradually reopen public recreation facilities with safety measures amid COVID-9 pandemic. (Photo by Liang Sen/Xinhua)

A family visits the reopened VanDusen Botanical Garden in Vancouver, Canada, on May 1, 2020. Vancouver started on Friday to gradually reopen public recreation facilities with safety measures amid COVID-9 pandemic. (Photo by Liang Sen/Xinhua)

People line up with social distancing to enter the reopened VanDusen Botanical Garden in Vancouver, Canada, on May 1, 2020. Vancouver started on Friday to gradually reopen public recreation facilities with safety measures amid COVID-9 pandemic. (Photo by Liang Sen/Xinhua)

A woman wearing a face mask visits the reopened VanDusen Botanical Garden in Vancouver, Canada, on May 1, 2020. Vancouver started on Friday to gradually reopen public recreation facilities with safety measures amid COVID-9 pandemic. (Photo by Liang Sen/Xinhua)

A man with a face mask walks past a sign to remind visitors to stay apart at the reopened VanDusen Botanical Garden in Vancouver, Canada, on May 1, 2020. Vancouver started on Friday to gradually reopen public recreation facilities with safety measures amid COVID-9 pandemic. (Photo by Liang Sen/Xinhua)