This article intends to question changing spatiality and position of the "urban edge" in expanding cities, and argues its spatial manifestation as an "urban fissure". The term "edge", which basically refers to the end line between two opposing milieus, became redundant in the expanded urban surface; and necessitates a critical review through a new concept. Edge, demarcating the communication/interaction line between two milieus, acts also as a "productive frontier" and generates an edgescape that subsequently appears as urban fissure in the expanded city. The Istanbul Land Walls, with their immense size and multi-layered spatiality, present a unique case in the search for urban fissure. The triple defense architecture of the Land Walls forms a complex system, composed of open and enclosed spaces: inner wall, outer wall, moat, terraces between the walls, towers and gates. Besides their architecture, the Land Walls have also triggered the generation of edge spaces on and around them: gates, Byzantine Imperial Palaces, Yedikule Fortress, bostans, cemeteries, sacred spaces, industrial sites, circulation infrastructure, recreational areas and neighborhoods. The coexistence of these spaces has formed a mural zone that has been molded by spatial removals, impositions or superimpositions throughout the course of the history. In this respect, the mural zone might be identified as a challenging ground, having diverse representations in different times: the material expression of the territorial defense for centuries, derelict defense architecture in Ottoman Istanbul, a ruined edgescape in the 19th century; an urban wilderness in the 1950s, and an urban interstice by 1980s. Especially after the 1980s, an increased number of (inter)national efforts/regulations/ planning attempts, informal occupancies and spatial removals/injections, have highly influenced the spatiality of the mural zone that ended up with spatial fragmentation, over-programming, and razed characteristic landscape fabric. To this purpose, this article discusses the multi-scaled and multi-layered spatiality and landscape of the mural zone through an integrated historical and conceptual reading that will present the mural zone as an urban fissure. Such analysis will reveal currently endangered spaces and landscape memories in the mural zone, and will liberate mural zone from over-programmed urban and landscape scenarios.