TIL Saskatchewan, Canada has sand dunes covering an area of over 1900 square km (733.6 square miles) and are usually 15-20 meters tall (49 - 65 ft).

https://www.todocanada.ca/great-sandhills-hike-this-unique-desert-in-saskatchewan/

https://www.reddit.com/r/todayilearned/comments/15i19s4/til_saskatchewan_canada_has_sand_dunes_covering/