(in English) The topic of the diploma thesis is to compare the WebArchiv with selected foreign Web Archives, which are responsible for preserving the national cultural heritage. The introduction briefly explains the history of Web Archives and typology of harvesting. Next parts deal with the history, legal aspects of archiving, selected types of harvesting, Web resources, systems, accessing and evaluation the Czech (WebArchiv), Australian (Pandora) and British archive (United Kingdom Web Archive). The text continues with an evaluation of the selected archives that mentions strong and weak properties and possible solutions. In conclusion, outlines the problematic aspects of archiving, which must be addressed in the future. [Author's abstract]