At the first city's restructuring plan in 1899, for the reason of organize the streets and through the roads, the government destroyed part of the city's walls and removed all Qing Dynasty buildings (such as temples) inside the city. At the first formal urban plan in 1990, the government not only filled all the moat, but also removed the wall that obstructed the through roads. West gate was also removed at the same time.
在第一次市區改正計畫中（1899年），台灣總督府以街地整理與貫通道路為由，將部分城牆連同城內原有的清代建築物（如文廟、武廟）等一起予以拆除。1900年，台灣歷史首次正式實施的都市計畫中，台灣總督府不但將所有護城河填平，並開始拆除妨礙道路貫通的城牆，西門也就是在此時被拆除。
At the second city's restructuring plan in 1901, the original plan was to speed up the demolition of the walls and remove all the gates of Taipei city. But due to the strong backlash after the west gate has been removed, the government changed their plan and keep the four gates that haven't been removed. Except the four gates, the government removed all the walls of Taipei city in 1904. The stones from the demolition were mostly transported to the East Gate for built up the Taipei Criminal Office. And the rest of the stones were used for the refurbishment the buildings in the city or for build the sewers. (The government agencies built at 1900-1920 in Zhongzheng district might able to find the stones of the wall, such as the National Taiwan University Hospital, Taipei Hotel, Jinan Presbyterian Church, National Taiwan University Law School, Jianguo High School Red House, President House, the old Taipei city hall, Ximen Red House and other buildings.)
在1901年的第二次市區改正計畫中，原定是要加速拆除城牆及全數的台北城城門。但因為拆除西門後所引起的強烈反彈聲浪，台灣總督府改變了原計畫，留下了尚未拆除的北、東、南、及小南門。到了1904年，除了刻意留存的四座城門外，台灣總督府幾乎將台北城所有的城牆拆除。拆除下的石材則大多運往東門附近，建造台北刑務所，而剩下的石材則用來整修市區內的建物或用來建造下水道。（中正區一帶於1900-1920年間所蓋建的公家機關，都有可能出現城牆石的蹤跡，如台大醫院舊館、台北賓館、濟南基督教長老教會、台大法學院、建國中學紅樓、總統府、舊台北市政府、西門紅樓等建物。）
Taipei Criminal Office 台北刑務所/Taipei Prison 台北監獄
Taipei Criminal Office was originally repaired at the site of the Qing government office in 1896. However, due to the poor quality of imprisonment and the poor health equipment of the temporary prison, the Japanese government start to build the new prison in 1899.
台北刑務所原先是在1896年時借清朝參府衙門舊址（約是今日台北市立大學附設小學）加以修補而成，但是由於臨時監獄的監禁和衛生設備不佳，日本政府遂於1899年開始新監獄的興建。
The initial choice of the prison base was outside the south gate. After a year of the construction work, the area has been included in the scope of the urban planning, so they moved the prison base to the right side of the C.K.S memorial hall of today. Meanwhile, based on the urban planning, the Japanese government decided to remove Taipei city walls, and reuse the stones from the demolition as the building material of the prison. The recycle and reuse of the Taipei city wall made Taipei Criminal Office became the only stone made prison in Taiwan.
最初選定的監獄基地是在南門城外，興築工程進行了約一年，卻因該區被納入都市計畫範圍，只好重新購地，將基地遷至今日中正紀念堂的右側。同時，基於都市計畫的施行，日本政府下令拆除台北城牆，並決定利用拆除的城牆石，作為監獄的建材，使用於建築物的地坪、監獄圍牆和內部隔間牆、部分建築物，以及地下水道，用以填補重新購地造成的成本。而台北城牆的拆除和再利用，也讓台北刑務所成為全台唯一石造的監獄。
During the period of 1944–1945, Allied airmen who had been shot down or crashed while on patrols over Taiwan were held in the Taipei Criminal Office by the Japanese Army. On May 29, 1945, 14 of these allied airmen were given a "mock trial" and sentenced to death. The execution took place inside the prison courtyard only 58 days before the end of World War II. When the war ended, the rest of the men were released and returned home.
二次大戰時期，台北刑務所成為日本政府關押與處決聯軍戰俘的處所。1945年5月29日，在一場日軍安排的假審判中，14名美軍飛行員在此無辜的被判處死刑，當天距離戰爭結束僅58天而已。其他戰俘則於戰爭結束後被釋放返鄉。
Taipei Criminal Office was still used as Taipei Prison after the Japanese government left Taiwan, but since part of the prison was destroyed before the end of the war, and the equipment of the prison is too old to use, Taiwan government sold the land of the prison and buy a new place at Taoyuan for build a new Taipei Prison. The buildings of Taipei Prison were mostly demolished, only the walls of north and south are survive. It became the historical relic in Taipei in 1998.
台北刑務所在日軍撤離台灣後改名為台北監獄繼續被使用著，但因為監獄的一部分在戰爭結束前被炸毀，且因監獄的設施太過老舊不堪使用，台灣政府出售監獄土地做為資金，在桃園買了一塊土地另建新的台北監獄。今建物全部拆除殆盡的臺北監獄，只剩南北兩邊的圍牆被保留下來。並於1998年被台北市政府列為古蹟。
The cache is hidden near the north of the prison wall. You could also visit the south of the prison wall with the reference point. (It might be difficult to view the whole south wall since it has been surrounded by the government due to the safety reason. But you could still discover where the wall is once you arrive the reference point.)