Beijing, Shanghai, Guangzhou and Shenzhen (abbr. for 北京[Bei3 jing1] + 上海[Shang4 hai3] + 廣州|广州[Guang3 zhou1] + 深圳[Shen1 zhen4])
trad. 北上廣深
Also written 北上廣深【Běi Shàng Guǎng Shēn】
Beijing, Shanghai, Guangzhou and Shenzhen (abbr. for 北京[Bei3 jing1] + 上海[Shang4 hai3] + 廣州|广州[Guang3 zhou1] + 深圳[Shen1 zhen4])
trad. 北上廣深
Also written 北上廣深【Běi Shàng Guǎng Shēn】