Passage: The most notable and recognizable landmark of the city is Piotrkowska Street, which remains the high-street and main tourist attraction in the city, runs north to south for a little over five kilometres (3.1 miles). This makes it one of the longest commercial streets in the world. Most of the building façades, many of which date back to the 19th century, have been renovated. It is the site of most restaurants, bars and cafes in Łódź's city centre.

Question: The buildings architectures dated back to when?
the 19th century