Original sentence: The structures have been dated to the 19th century CE and they may originally have been a byproduct of contemporary agricultural techniques
Edited sentence: Most of his search and evidence can be seen in the Gűimar Pyramids Museum of Tenerife, Spain.There are extensive research made and evidence collected by Norwegian Anthropologist Thor Heyerdahl that are dating the pyramids well before the time mentioned by other scholars.There are some scholar dating them to 19th century CE and they are also believed originally to be a byproduct of contemporary agricultural techniques