The Hardell-Nilsson case studies are groundbreaking because, incredibly, they study human beings in a real-life 5G environment for the very first time. All four studies describe how previously healthy people very quickly developed symptoms of microwave syndrome after 5G phone masts were installed above or opposite their accommodation at distances of between five and 60 metres. Most of the symptoms disappeared within days of them moving to less irradiated accommodation, but reappeared when they returned to the strongly irradiated accommodation.