The primary objective of this paper is to present opportunities for creating virtual 3D models of defunct historical buildings, reconstructed on the basis of archival and field research, and the effective promotion and visualisation of such models through a thematic web application. The secondary objective is to increase the tourism potential and attractiveness of the various historical sites and the studied region. The comprehensive methodical processing of documents and the creation of 3D models of objects and other digital visualisation requires not only high-quality programmers and graphic artists, but especially scientists who create historically-relevant descriptive texts, real schemes, and historically acceptable models that can be computer-processed, visualised, and used as an effective tool for the development of tourism. Research and follow-up activities require an interdisciplinary approach, i.e. the cooperation of experts from various disciplines. The research processed in this study points out that even simple, now widely available modern means of communication, such as websites, can be effectively used for the promotion and publicity of this type of attraction. High-quality 3D models and visualisations of buildings and specific destinations, or cultural and technical monuments, can thus become available to tourists also outside museums. This paper introduces the opportunities of digital presentation of preserved, partially defunct and, especially, completely defunct historical buildings and sites that are often almost unknown to tourists. In many cases, only their shells or foundations remain. In terms of cultural heritage conservation and monument protection, these sites are often among the most important religious buildings from various historical periods. This study focuses on the Middle Ages and locations in Slovakia (former Hungary), and presents a methodology that is generally applicable for the research and visualisation of any similar cultural sites, and thus opening up their potential to tourists.