In a new essay, published in People magazine on Wednesday, Orlando Bloom calls his experiences as a UNICEF Goodwill Ambassador working with Ukrainian refugee mothers and children “something he’ll never forget.”

Bloom recently visited Moldova — a country on Ukraine’s southern border — where he worked in what’s known as a Blue Dot, described as “safe spaces that have been set up by UNICEF and partner organizations … for women and children arriving from Ukraine.” Bloom writes that such places not only provide information for parents about next steps but also give them a chance to rest while their children are looked after. They also help unaccompanied and separated children crossing the border, both in terms of identifying them and ensuring that they’re protected from exploitation and trafficking.

“As a father, I would do whatever it took to protect my children, yet I could barely begin to comprehend the devastating decisions these mothers were forced to make,” he writes about seeing the lengths arriving Ukrainian mothers had gone to in order to escape, along with their children, Russia’s ongoing attacks in the country.

Among the stories he recounts are that of a mother who had recently fled Ukraine with her children, including her “visibly shaken, still terrified” two-year-old boy, after her neighbor’s house was bombed. Recalling their conversation, Bloom notes that she said she had “risked it all” for her children, and was grateful that “at least my children aren’t going to get scared by alarms” or “only see the world through a window.”

Another individual Bloom met is a Moldovan man named Igor, who had brought toys for the children at the Blue Dot and who was working as a host family for refugees.

“Together, with the 2.5 million children internally displaced inside Ukraine, [the war has led to] one of the fastest large-scale displacements of children since World War II,” Bloom writes, echoing late March figures shared by UNICEF executive director Catherine Russell. “So much trauma for so many young lives. None of these children will ever be the same.”

Reflecting on his trip after returning home, Bloom said he was still thinking about everyone and everything that has been left behind by Ukrainians fleeing the war, and what it might be like for his own children “to suffer the pain and grief of losing their homes and everything they’ve ever known in a senseless instant.”

Still, Bloom wrote that he found hope in the compassion and generosity of the Moldovan people. “Through all this turmoil and uncertainty, I’m grounded by the kindness of people like Igor,” he said, “and I’m hopeful that the children living through this crisis will never forget the small gesture of a stranger.”