The answer to all of them is Baghdad.
The Islamic Golden Age was a period of cultural, intellectual, scientific, and economic flourishing in the Islamic world between the 8th and 14th centuries. The main center where this cultural movement took place was Baghdad, the capital of the Abbasid Caliphate.
Artistic writing forms such as calligraphy flourished here: the most prominent medieval Islamic calligraphers lived and worked in Baghdad, like Ibn Muqla, Ibn al-Bawwab, Ibn al-Musta'simi, and Fakhr un-Nisa.
Scholars worked together here to study and translate ancient texts: with the support of the Abbasid Caliphate, scholars from Baghdad took an active policy of searching for books of many fields around the world, bring them to Baghdad and translating them into Arabic. Every manuscript that occasionally entered into the city was immediately translated, with the original kept in the libraries and the copies delivered to the owners. Thanks to this policy, texts of ancient Greek, Indian, Chinese, and Persian philosophers, physicians, and scientists were translated.
The gathering place of intellectuals, called the "House of Wisdom," was here: the House of Wisdom was a public academy, an intellectual center, and a private library of the Abbasid Caliphate in Baghdad. It was responsible for most of the translations made in this city.