For the centennial of the Republic, we offer a novel reading of Turkey’s past and present focusing on its most iconic space: Anıtkabir, the Mausoleum of Atatürk, the founder of the polity. Taking the Mausoleum as our lodestar, we map how the notion of sacredness traverses secular and Islamic faultlines and acts as a force both fostering and mediating conflict. Completed in 1953, the Mausoleum mirrors the ascendancy of a secular and republican nationalism and citizenship over an Ottoman and Islamic public sphere. Despite widespread transformations taking place in Turkey in the last two decades, it is still the most important political space in the country. However, the meanings associated with Anıtkabir have evolved considerably as Islam has gained significant public visibility. Our novel conceptualization of Anıtkabir has two core elements. First, we define Anıtkabir as a sacred space; a location profoundly valued by a large number of people for paying their respects to the Republican founder, expressing their commitment to the political entity he inaugurated, and taking a stance against perceived threats to his legacy. In addition to being a space for official ceremonies involving both Turkish leaders and foreign dignitaries, it continues to attract ordinary people. Next, we define the Mausoleum as a megaproject, which is a highly symbolic and massive public undertaking involving major time, labor, and resource commitments as well as coordinated and long-term, at times intergenerational, efforts to complete. Anıtkabir’s construction spanned a good decade that were also transitional years between the single-party regime and multiparty politics, each with their distinct governing ethos. Studying Anıtkabir enables us to offer an original account of how political power was crafted, how national identity was constructed and reconfigured, and how the republic was imagined shortly after its founding. To make these points, we examine prominent newspapers with opposing ideological orientations, such as Cumhuriyet, Tan, Ulus, and Zafer during intense public debates around Anitkabir’s construction, the architectural competition and the different visions of the public implied in competing projects, and finally, the shifts in choices that accompanied the transition from a single-party regime to a multi-party democracy. We argue that, as a sacred space and a megaproject, the Mausoleum is not only a hegemonic symbol of secular-nationalism, but it also continues to represent controversy and resistance about Turkey’s identity. Overall, our paper brings to light how the politics of Anıtkabir fits within a critical assessment of Turkey’s republican centennial.