For this week’s photo challenge, Ben Huberman asks us to explore limits, borders and dividers. From the challenge post, “Boundaries impose limits on us, whether they’re social constructs or real, physical objects…” You can view the entire challenge post here.

In the opening photo, the iconic lift bridge at Duluth Minnesota presents alternately a barrier to boat traffic between the harbor and Lake Superior; and a barrier to automobile traffic from passage along the road into the harbor area. A man-made breakwater protects boats in the harbor, however access to the harbor by vehicles was needed, so a road was built. The lift bridge allows for an opening in the breakwater so that ships may pass through. It accommodates automobile traffic most of the time, until a boat or ship needs access to or egress from the harbor. Then traffic is stopped while the bridge is lifted out of the way.

In the 16th century, the town of Cartagena, Colombia grew to be a trade center. Located at the northeastern end of South America, the wealthy city became the target for Caribbean pirates. One of the city’s defenses included a large wall around the city. In modern times, people found the wall to be constraining, so there are now many openings in the wall to allow the flow of modern (and as depicted in the above image), not so modern traffic into and out of the city center.

The north and south American continents limited easy passage from the Atlantic to the Pacific Ocean. Until the early 20th century, the only way a large watercraft could traverse between the two oceans was via Cape Horn at the southern tip of South America. The development of the Panama Canal with its system of locks and lakes now allows ships to cut off many miles of travel making the journey between the two oceans a trip that typically lasts less than a day.

My final image is of a gate that appears to be pretty much useless, considering the V-shaped opening in its center. This gate is located at the boundary of Maricopa County’s White Tank Mountain Regional Park. The view looks outside the park toward an equestrian, hiking and biking trail. The Maricopa Trail is a connecting trail that will eventually cover 376 miles. Soon to be completed, the trail connects the county’s ten parks that surround the Phoenix metro area. The gate allows the passage of hikers and bikers, but prohibits access to motorized vehicles. The Maricopa Trail grand opening will feature the Prickly Pedal Race on January 23, 2016.

John Steiner