I park the truck near the World War II memorial and begin a routine walk along the causeway at Pleasure Bay in South Boston. The winter air is crisp and I zipper my coat against the chill wind coming off the harbor.

Doing the loops is an exercise that tens of thousands of Bostonians have undertaken over the decades. I start toward the new pavilion where the causeway makes a sharp left turn to Castle Island.

People pass, some with a smile or a greeting but most silently, as they hunker down against the breeze. There are fast walkers, slow walkers, dog walkers, casual walkers, and runners.

The distractions are many and varied. Even at this time of year there are wet-suited kite boarders skimming across the bay harnessed to colorful, billowing sails. They toy with the wind as they leap and turn, aquatic acrobats riding unseen currents.

Overhead the planes are coming and going from the airport. I try to identify the airlines as they scream overhead on their downward path and watch as departing aircraft strain for altitude as they climb over the city. Looking in that direction I can see the sleek bulk of a cruise ship tied up at Black Falcon Terminal.

The harbor islands are off to my right as I make the turn at the pavilion. I see Long Island, where I worked during the summer in the 1950s when I was a high school student, with its breathtaking view of the city. Nearby is the recently elevated Spectacle Island with its grassy dome, courtesy of the Big Dig.

I try to imagine what the harbor looked like 150 years ago during the Civil War when Castle Island was actually an island where union troops, quartered at Fort Independence, awaited transportation to southern battlefronts.

How far was the island from the shore and what did the South Boston shoreline look like then? It was likely rural with farms and fields along what is now Day Boulevard. Along the inner harbor were the masts of sailing vessels discharging and loading cargo. Merchant and naval ships under sail could be seen entering and leaving the harbor.

My reverie is interrupted when an attractive young woman in a running suit jogs by as I approach Castle Island. I remember twenty years ago when I would regularly drive to Carson Beach after work and jog from there to Castle Island and back in less than an hour. The spirit is still willing but the knees are not.

Around the island I walk as a commuter boat steams out of the harbor on its way to Quincy or Hingham. There are still a couple of hearty souls trying their luck on the fish pier. Past Sullivan’s, now closed for the winter, I have to decide whether to take the shore route or return along the causeway.

More often than not it depends on the wind. It’s a lot colder on the causeway. There are far fewer doing the loop in winter. With no place to eat, the bathroom closed and the wind chill factor, it is not as appealing as in the softer seasons.

Yet with its combination of sea, shore, and varied distractions, it is the best place in the region to get some exercise, contemplate a little history, share a smile with a passing stranger, and speculate on what the future may bring.

For my money, the Charles River Esplanade and World’s End in Hingham are a close second. I also enjoy walking in Pope John Paul II Park but there’s not much going on there.

Some have suggested the proposed Boston casino should be located on one of the islands, with ferries taking patrons from various locations around the harbor. There certainly could be no more attractive site, and the views from the islands are spectacular.

Perhaps in a few years those doing the loop will have another distraction. They will look across the bay to the Boston Harbor Casino & Resort on Long Island as water taxis shuttle patrons from a pier at the original site of Kelly’s Landing.

A good walk is like spending quiet time with an old friend.

James W. Dolan is a retired Dorchester District Court judge who now practices law.