What are 3 Significant accomplishments (art/architecture/literature/etc.) from the Ancient Islamic nation?

Answer 1

The first three that come to mind, and there are many others, are:
1 - The numbering system we use. We no longer use Roman numerals, we use Arabic numerals
2 - Architecture, including the Arabic dome and the Arabic arch. These are repeated in numerous places and ways, all the way from Longwood Plantation house in Natchez Mississippi to the Egyptian Theater in Hollywood
3 - Sanitation systems. The Arabs, unlike the Christians of the Middle Ages, actually believed one should bathe before going to pray. When the Arabs/Moors invaded Spain they were appalled at the horrible sanitation systems and in one town the sewage running down the streets was so bad they named it, in Arabic, the "River of S**t" ... of course we know it today as the city of Guadalajara.
4 - ..... you could also mention math, geometry, science, medicine, and much much more