This is an early 20th century woven decorative tapestry. Tapestries are made on a loom with a warp and a weft. In the early centuries, during the Medieval and Renaissance eras, tapestries were considered more valuable than gold and silver. They were castle wall sized and used primarily as insulation during cold weather months as well as an overt display of wealth. Making tapestries has become more mechanized and the sizes have reduced significantly to be decorative wall art as opposed to insulating walls. Yours is likely Flemish (Belgian) based on the Cathedral and windmill in the background. The estimate is based on actual recent past recorded auction sales. Retail 'asking' prices may be higher and may vary.