COPENHAGEN, Denmark (AP) — The Duchess of Cambridge met Wednesday with Denmark’s popular monarch, Queen Margrethe, and her daughter-in-law, Crown Princess Mary, in Copenhagen as part of a two-day visit to learn more about how Denmark has led efforts in early childhood development.

Kate slid down a slide at the Lego Foundation PlayLab and hung out with young children in the woods at a forest kindergarten as part of the trip with her Royal Foundation Centre for Early Childhood, the first time she has taken the work of her institution to the international stage.

Before her solo trip to Denmark, the duchess revealed she spent a recent school vacation playing with Danish-made Lego bricks with her three children — Prince George, Princess Charlotte and Prince Louis — who were jealous she got to visit the Lego Foundation.

“My children are very jealous they weren’t coming to see the Lego Foundation. They were like, ‘hang on, there’s Lego and we’re not coming?’” said Kate, who arrived in the Danish capital on Tuesday and visited the Infant Mental Health Program at the University of Copenhagen.

On Twitter, the royal said that Tuesday “was all about understanding the very earliest stages of a child’s development here in Denmark.” She said that on Wednesday the focus was on children’s mental health and wellbeing.

The Duchess of Cambridge took a woodland walk with children and had a go at chopping a log while visiting a forest kindergarten in suburban Copenhagen Wednesday. She also visited the downtown Copenhagen Danner Crisis Center, a shelter that helps women exposed to domestic violence.

In 2011, Kate visited the UNICEF Supply Division Center in Copenhagen with her husband, Prince William, and the heir to the Danish throne, Crown Prince Frederik and his Australian-born wife Mary.