## 1 Introduction  
Over time, the way to understand the concept of accessibility in our society has changed. What used to be a purely physical concept has since become a cognitive and sensorial concept. We do not only have to provide physically accessible buildings to everyone, regardless of their physical condition [1]. We can and must also build digital worlds that guarantee access to culture (architecture, sculpture, painting, visiting museums, etc.) independent of which county we live in or our economic resources. The concepts of the metaverse and digital twin are particularly important in this 2.0 accessibility era [2].  
These new digital worlds become especially important when they are applied to the field of architectural heritage and are made tangible by new technologies, such as methodologies for the generation of digital twins [3], integration in BIM models (building modeling information) and HBIM (Historic Building Modeling Information) [4, 5], AI (Artificial Intelligence), and augmented reality (AR), virtual reality and mixed reality [6, 7].  
In countries such as Spain, where one of the most important economic activities is tourism, the pandemic highlighted the need to generate new tourist and cultural resources that are not dependent on one's physical presence. In 2019, tourism activity in Spain accounted for 12.4% of GDP (gross domestic product), and in 2020, it accounted for 5.5%, according to the INE (Spanish National Statistics Institute). Achieving universal accessibility that allows reaching each and every person, regardless of their limitations, and committing to the dissemination of cultural heritage through tools such as digital twins [8, 9] are essential for the county's economic growth in the near future.  
Thanks to the evolution of technology since the first 3D glasses were proposed by [PERSON] in 1968 [10] (Figure 1) and the creation of new tools, we can establish workflows that adapt themselves to this new concept of universal accessibility. We currently have new techniques and technologies for capturing reality, such as photogrammetry using unmanned aerial vehicles (UAVs), terrestrial photogrammetry or a terrestrial laser scanner (TLS) [3; 11; 12; 13]. We also have new ways of processing this documentation through software tools that enhance the value of the data and generate novel workflows that give rise to HBIM [14; 15]. In this way, HBIM is a working concept made possible by new technologies that allow us to integrate all of the information available on a cultural property, and, as we shall see, it also facilitates new ways of disseminating it through digital twins and metaverses.  
Figure 1: (**a**) On the left: [PERSON] working with Sketchpad III and (**b**) [PERSON]’s head-mounted 3D display (1968). Both devices were precursors of current technology influencing cinema and science fiction: (**c**) _The Matrix_ (1999), directed by the [PERSON] sisters; (**d**) 3D Glasses or SegaScope 3-D from the Master System, designed by [PERSON] (1987); (**e**) Google Cardboard as a low-cost VR system (2014); (**f**) Ready Player One (2018), directed by [PERSON]; and finally; (**g**) [PERSON] at an Oculus demo; (**h**) Valérian et la Cité des mille planétes (2017), directed by [PERSON], proposing an alternative to tourism through virtual reality.  
The accurate documentation of our heritage will guarantee efficient conservation and management that will gradually achieve the aforementioned universal accessibility [16], accessibility that must use all of the tools at its disposal to reach the population without discriminating against anyone, from traditional documentation methods [17] to new, much more dynamic databases (Figure 2) [18; 19]. In our case, we propose an improvement of the concept of accessibility through augmented reality (AR) and virtual reality (VR) applied to heritage [20; 21; 22; 23].