违章建筑
wéizhāng jiànzhù

“违章” v. break rules and regulations（Source: 《新世纪汉英大词典》）
“建筑” n. building; structure（Source: 《新世纪汉英大词典》）
“违章建筑” n. illegal building

新闻例句

被网友称为“北京最牛空中别墅”的违章建筑引发舆论强烈关注。（Source: 海外网）

Dubbed as the “most extraordinary penthouse in Beijing”, the illegal building caught great public attention.