Second, Northern Lights. Its a fantastic phenomenon of our world which every human must see.
Third, ice kayaking. Kayaking is normal but ice kayaking is extraordinary and its a must-try thing at Greenland.
Fourth, visiting icefjord. You can travel along the ice and find you way out through the another way.
Last but not least, sledge control. You will be given chances to control your way through ice with only few strings in your hand.