The karst topography is a unique topography created by long-term salivary actions such as rainwater in which rocks that are soluble in water, such as limestone. Most rocks dissolve only in very small amounts in water, but limestone gradually melts over time to create various forms such as doline and longitudinal flow (limestone cave). The development pattern of these karst topography varies depending on various factors such as environmental conditions, the thickness and composition of limestone, and the circulation of groundwater.

As such, a caste is a product of constant communication with nature over a long period of time. Architecture is no different. Architecture is a structure built on the ground and should be a space that interacts with the environment and contains the history and memories contained in the ground. The role of an architect is to discover, interpret, and embody the meaning inherent in the land in its architectural form. Architecture must be reborn as a place that can flexibly accommodate the future based on the understanding of the long history and culture accumulated in the land, just as the caste topography is formed in the process of accumulating time. At this time, architecture finally reveals its existence as a living terrain.

Huam-dong, a village located at the western foot of Namsan Mountain, originated from a large rock called Dutupbawi Rock. In the past, people gathered as a place to pray for offspring, and during the Japanese colonial period, it was called Gyeongseong 府 坂, a mixture of Japanese and Western architecture. Later, the area was renamed Huam-dong with the liberation of Korea, and the remaining structures there left important traces of modern residential history. Due to its historical significance, Huam-dong has become an important place to remember modern Seoul's history.

The site faces Baekbeom Plaza Park along Sowol-ro and is located at an important intersection leading up to Namsan. The congestion of Seoul Station and building forests spreads out to the west, commercial facilities and old residential areas to the south, and the natural green areas of Namsan Mountain to the north. Can architecture be harmonized and independent on this complex intersection of elements? And can it be a flexible place that encompasses the past and the future? I couldn't get out of my head these questions. But in the end, we came to the conclusion that 'if this land has a role that it has been given here now, wouldn't architecture discover its meaning on its own in its journey?'

It is reckless for an architect to conclude the role of the land and the meaning of the existence of architecture like a creator. Rather, it may be necessary to have an attitude of contemplation that puts down reason for a while, accepts the surrounding elements 'as they are', and watches them as an observer. According to the phenomenology of modern philosophy, it is possible to properly grasp the object only when one wants to exclude prejudice and capture the pure essence of an object. Likewise, in the construction process, one had to put down prejudice and listen to the natural demands and possibilities of the ground. This process of withholding judgment on the object and temporarily tying it in parentheses is to admit the inability of reason to prevent preconceived notions from seeing what the ground really wants. By taking the state of 'judgment suspension (epoke, epoché), which is a method of phenomenological reduction, the design proceeded from looking at the object with a pure and receptive attitude that appears in the architectural process itself.

The design process was a process of constantly responding to the relationship with the surrounding environment and trimming the shape for self-growth, just like the formation of a karst topography. Just as the topography causes erosion, the process of shape reacting step by step and transforming was purely accepted and embodied one by one in the drawings. The form established in accordance with basic building laws such as the limit of sunlight line, height limit, and floor area ratio was clearly established like a dolmen, but it was only a rough mass that was cut off from the external environment. In order to place this naturally on the extension of the topography, the front part facing Namsan was opened with transparent glass to bring the nature of Namsan into the building. However, the appearance of the building standing like a folding screen against Namsan gave the feeling of confronting nature, and rather, it seemed to violate the energy of Namsan. At this time, while looking at the fortress of Namsan across the street, I thought of the gun hole of the wall. Based on this, I tried to take a shape where the energy of nature could flow by eroding the center of the building. This was like a method of opening the chakra in the heart of Indian philosophy and drawing a circulation with nature by penetrating through the center of the building. The terrace space in the eroded center induced the flow by diagonally

moving the eroded heart to the green glass surface so that the energy of Namsan Mountain could resonate together and penetrate deeply into the inside. In this way, a confident and natural front was formed. However, for pedestrians on the side of the road, another turn of the fortress appeared, and the side of the road leading up to Sowol-ro still felt stuffy. To solve this problem, the parking and entry space on the lower floor was composed of a piloti opened down the hill along with a small landscaping space, giving breath away from the streets of the city. On the rear side facing the distant urban landscape, the two parts were eroded as if they were recessed, and the terrace spaces were arranged so that they could react to each other between the inside and outside. The terrace, where you can enjoy the view of the city, pushes deep into the vertical void space inside and connects the inside and outside.

Urban and architecture grow closely with each other. Architecture can function as a sustainable space only when it understands and respects the history and culture of the land, and reflects the needs of the times, just as the karst landscape is gradually formed through interaction with nature. This architecture in Huam-dong will serve as a medium connecting the city and nature, and the past and the future. Just as nature sculpts terrain, architecture hopes to be an entity that constantly communicates with its surroundings, changes, and grows. Like the terrain containing the sublime of nature, the Huam karst is expected to be reborn as a cultural terrain that grows with the city over time.