I believe, that in deep underground on Earth, has the least effect of weathering. It is <span>where there are no interactions with air, and very limited reactions with water, and nothing that breaks apart. I hope this answer helps.</span>
The City Wall of Nanjing<span> (</span>Chinese<span>: </span>南京城墙<span>; </span>pinyin<span>: </span>Nánjīng chéngqiáng<span>) was designed by </span>Emperor Zhu Yuanzhang<span> (r. 1328–1398) after he founded the </span>Ming Dynasty<span> (1368–1644) and established </span>Nanjing<span> as the capital 600 years ago. To consolidate his sovereignty and keep out invaders, he adopted the suggestions of advisor Zhu Sheng to build a higher </span>city wall, to collect grains and to postpone the coronation. Then, he started to build the city wall. It took 21 years to complete, and used 200,000 laborers to move 7 million cubic metres of earth. The City Wall of Nanjing was among the largest city walls ever constructed in China.[1][2]<span> The enclosed </span>Nanjing City<span> is about 55 square kilometers.</span>
The biggest one was Operation Overlord (D Day)
