Markers are important semiotic devices of tourism discourse in the creation of images of World Heritage Sites (WHS) as tourism attractions. However, they display information and explain its significance according to the discourses and social assumptions about heritage that govern their use. As alternative discourses emerge alongside mainstream tourism discourse, these introduce new dynamics in the use of markers, which may give rise to competing images of a same WHS attraction. This largely under-investigated issue is at the core of the present paper, which focuses on a multimodal discourse analysis of markers in sample web-based tourism and indigenous discourses. While the main aim is to unfold the evidential-type of information and the epistemic-type of evidential information markers provide of a same WHS across these discourses, the ultimate goal is to highlight the practical implications the quantitative and qualitative results of the study may have for ESP learners of tourism discourse.