The purpose of this paper is to inform the reader about the simplicity of monitoring the Earth's surface, a description of possibilities provided by remote sensing, ease of data collection, and their processing on the example of urbanization of the city of Varaždin. The paper is structured purposely to explain how images for remote sensing are created, how satellites and their sensors work, from which we obtain recording and data needs. The paper elaborates the quality of recordings that we can get, as well as their resolutions. Numerous satellite missions intended for imaging the Earth's surface are listed, and their qualities and possibilities of using images from these missions are described. In this paper, images of the Landsat satellite mission were used, where images from three different satellites (Landsat 5, Landsat 7 and Landsat 8) were used depending on the analyzed period.. Images of the area of the city of Varaždin from 2000, 2005, 2010, 2015 and 2020 were analyzed. The analysis of the supervised classification was performed in QGIS. The results of the research obtained from QGIS were processed in Microsoft Excel and Word and are presented pictorially, graphically and tabularly. The results show the urban development of the city of Varaždin and they reveal changes in the assignment of parcel plots and the increase in the number of buildings built in the city of Varaždin every five years from 2000 until today.