The master's thesis describes an area of augmented reality and the process of developing a smartphone app which demonstrates the use of augmented reality in real life surroundings. Augmented reality is a way of presenting the real world with various virtual computer elements added. Within the practical part of my research, I have developed a smartphone app for the Android OS, on the basis of available libraries for augmented reality in C and Java programming languages. By referring to the user's current location and by the digital processing of images, the application recognizes buildings displayed on the smartphone's screen and - using augmented reality - provides the user with the pictures of those same buildings dating from the beginning of the 20th century. At the same time, then, the user is able to simultaneously and interactively examine the appearance of same buildings from two different historical periods. In future, using the algorithms developed for this occasion, I will modify the application in order for it to be able to augment other objects from the real-life environment, not only buildings.