Modern, industrial Bursa is built around the mosques, mausoleums and other sites from its incarnation as first Ottoman capital. Despite being built-up and somewhat chaotic, its durable Ottoman core and abundant parks keep it remarkably placid in places. For some fresh air after pounding the markets, the soaring peaks of Mt Uludağ (Turkey's premier ski resort) are nearby, with Çekirge's thermal hamams en route.
Bursa is also known as the city where Ottoman architects left behind the Seljuk Turkish architecture of the past and developed their own Ottoman mosque architecture (based partly on Persian and Byzantine models) which then saw its greatest expression in the sublime Ottoman mosques of Edirne (second capital of the empire) and Istanbul (third and last imperial capital). Anyone with an interest in architecture should see that city.