Wall Street is named for an actual wall. In 1653, Peter Stuyvesant ordered a barrier of dirt and 15-foot wooden planks built across the northern edge of New Amsterdam, nine feet tall and more than 2,300 feet long, to stop an overland attack. Enslaved Africans were forced to build it. After the English dismantled it in 1699, the wide avenue it left behind became the site of a municipal slave market that operated from 1711 to 1762, with the city taxing every sale.

This episode follows that eight-block street as it turns from a place into an idea. Traders gathering under a buttonwood tree signed the Buttonwood Agreement in 1792, the origin of the New York Stock Exchange. The Erie Canal made New York the money capital of America, and in 1884 Charles Dow began tracking 11 stocks to give investors a single reading of the market. The story continues through the 2008 crisis, Occupy Wall Street, and a present in which most trading happens in data centers far from the street itself.

• Twenty-four traders signed the Buttonwood Agreement to curb manipulative auctions and fix a standard commission, charging outsiders more.
• Most of Dow’s original 11 stocks were railroads, and his Customer’s Afternoon Letter grew into the Wall Street Journal.
• By 2018 the NYSE’s market capitalization reached $28.5 trillion, and its trading floor runs on 3,500 kilowatts and 200 miles of fiber optic cable.
• The episode explains how subprime mortgages were bundled into mortgage-backed securities, sold worldwide, and bailed out through TARP.
• BATS, a trading platform run by about 33 people in Kansas City with computers in New Jersey, captured a 9 percent share of U.S. stock trading.