Detailed Instructions: In this task, you are given a sentence in Persian, and your task is to translate it into English.
Q: او در سال‌های پایانی دهه ۱۹۹۰ اثرات مهمی در هنر شهری اروپا از خود به جا گذاشت.
A:
His then unusual form of artistic expression, street art, balanced on a high wire between guerilla activism and mainstream art.