Surah Al-Fajr 89:7

إِرَمَ ذَاتِ ٱلْعِمَادِ

[With] Iram - who had lofty pillars,

Translation: Saheeh International

Tafsir

Iram — these were the former people of ‘Ād Irama is an explicative supplement or a substitution and it is treated as a diptote because it is a proper noun and feminine — of the towering ones that is to say the tall ones — the tallest one among them would reach four hundred cubits —

Excerpt from Tafsir al-Jalalayn, commentary on 89:7, via Quran.com. The reader has the full commentary and 9 more tafsirs.