This article remembers key events that have shaped Wall Street history.

The world's first transatlantic telephone cable opened for business on this day in 1956. The TAT-1 -- a joint venture between AT&T (NYSE: T), the British Post Office, and a Canadian telecom -- stretched from Scotland to Newfoundland, connecting Eastern and Western hemispheres. The four-way conference call between London, Ottawa, New York, and Chicago was heard by all parties "as clearly as if [they] were making a local call," according to the Chicago Tribune.

The $42 million cable ($356 million today) had been under construction for three years and could handle 36 simultaneous conversations. Previous transatlantic communications had either taken place via telegraph cables that had been in place since 1858 or via radio waves, the latter of which suffered signal breakdowns over long distances.

The new connection couldn't stop a mild bear market that had begun that April. The Dow Jones Industrial Average (INDEX: ^DJI) had fallen nearly 8% by September 25, 1956, and would bottom out just over a year later. The index's immediate reaction to the call was a decline of 1.4%, but Dow component AT&T remained flat.

Investing in AT&T the day its first transatlantic cable opened for business would have earned you an annualized return of 5.5% for the 56 years that followed. This doesn't count any reinvested dividends, and also can't assess any returns you might have gained from stocks created by AT&T's 1984 antitrust breakup. The Dow on the other hand has posted an annualized growth rate of 6.2% over the past 56 years.

Transatlantic legacy
The use of better and faster transatlantic telecommunication cables over time eventually led to the decline of satellites as telephone communications hubs, and have rendered the telegraph obsolete. When the TAT-8 -- the first transatlantic fiber optic cable -- was laid in 1988 by AT&T, France Telecom (NYSE: FTE), and BT Group (NYSE: BT) (then British Telecom), it boasted the ability to carry 40,000 simultaneous conversations, a capacity increase of 111,000% in 32 years.

The Internet's growing popularity led to the creation of ever-larger transatlantic telecommunications pipelines, with TAT-14, the latest to come online, boasting a 3.2 terabit-per-second capacity. That might seem like a lot, but Cisco projects that the world will create 966 exabytes of Internet traffic per year by 2015, which amounts to 257 terabits every second.

The rise of high-frequency trading, parallel to the Internet's growth, has also spurred the construction of specially focused transatlantic cables, so that HFT firms can take full, real-time advantage of any important trading moves happening across the pond. Hibernia Atlantic, the largest pipeline for HFT firms' exclusive access, can carry up to 10 terabits per second, and its response time from shore to shore and back is only 65 milliseconds.

These transatlantic cables have helped American companies extend their reach worldwide. Some have made better use than others, but connectivity is invaluable to any company that's out to dominate the world. The Fool's identified three globe-straddling brands that have the right combination of modern connected supply chains and old-school popularity to thrive for years to come. You can find out what makes them great investments in our free report -- click here for the information you need.