We landed at Shannon Airport at six in the morning and our vacation almost ended by nine. That’s when my friend and I went to cross a street in Galway. We looked to our left and stepped off the curb – the road was clear. Then a horn blared, we pulled up short, and a car screamed past from the right, barely missing us. Oh, yeah – people drive on the other side of the road in Ireland.

So why the difference? According to bigthink.com, the Irish and British custom of driving on the left side of the road dates back to the days when people traveled on horseback. Approximately 90% of people are right-handed, so horsemen held the reins with their left hand, leaving their right hand free to either shake hands with passersby or strike them with a sword. Think Game of Thrones.

In the 1800s, freight wagons played a vital role in the westward expansion of the United States. Drawn by multiple pairs of horses, the wagons were built without seats so every ounce of their load would generate revenue. Teamsters (so-called because of the teams of horses they drove) sat on the left rear horse, the best position for snapping their whips with their right hand. It was easier to see approaching traffic when it was to the left – so they switched to driving on the right side of the road.

In Britain, freight wagons were smaller than their American counterparts and drivers continued to ride atop the wagon instead of climbing down to the left rear horse. The custom of driving on the left prevailed, as it does in many countries that were once part of the British Empire.

What we do in the present connects us to the past. I drive on the right side of the road today because freight wagons helped our vast country expand two centuries ago.

Fitzgerald knew: So we beat on, boats against the current, borne back ceaselessly into the past.