Denmark attractions that are absolute must-sees include the enchanting Tivoli Gardens in Copenhagen, the historic Kronborg Castle in Helsingør, and the iconic Little Mermaid statue. Jelling's rune stones, a UNESCO World Heritage Site, and the cliff-side wonders at Møns Klint are also among the top things to see in Denmark. For an immersion in Denmark's Viking history, a visit to the Viking Ship Museum in Roskilde is essential.