This task is about reading the given passage and construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) its answer is a continuous text span from the paragraph. Avoid creating questions that (i) can be answered correctly without actually understanding the paragraph and (ii) uses same words or phrases given in the passage.
Q: By 1840, the Market Hall and Sheds, where fresh meat and produce were brought daily, became a hub of commercial activity. The slave trade also depended on the port of Charleston, where ships could be unloaded and the slaves bought and sold. The legal importation of African slaves had ended in 1808, although smuggling was significant. However, the domestic trade was booming. More than one million slaves were transported from the Upper South to the Deep South in the antebellum years, as cotton plantations were widely developed through what became known as the Black Belt. Many slaves were transported in the coastwise slave trade, with slave ships stopping at ports such as Charleston.
A:
What industry depended on the port of Charleston?