Vietnam’s Son Doong cave, the largest in the world, could hold a 40-story skyscraper inside. The pristine ecosystem has its own river and jungle. Despite its size, Son Doong wasn’t discovered until 1991. It was lost again for nearly two decades and was fully explored for the first time in 2009. (Photo by Jason Speth/HuffPost)

A view of the start of the 37th Gotland Grand National motocross race in Visby, Sweden on October 24, 2020. (Photo by Soren Andersson/TT News Agency via Reuters)

Lucinda Grange perches on the eagle's head on the corner of New York's iconic Chrysler Building in Manhattan, New York City. (Photo by Lucinda Grange/Barcroft Media USA)

With temperatures soaring and summer well underway, countless Americans will be spending their Independence Day weekend at the beach. Here we revisit some classic images from the turn-of-the-century to the 1930's of vacations by the sea, from Coney Island to Santa Monica.

A Guarani Mbya man smokes a pipe next to a cut tree as he occupies land as a protest against real estate developer Tenda which plans to build apartment buildings here, next to his indigenous community's land in Sao Paulo, Brazil, Thursday, February 6, 2020. In response to an injunction filed by the builder, a judge has authorized the eviction of the indigenous protesters from the builder's property. (Photo by Andre Penner/AP Photo)

Visitors browse in the starry Art Museum. Shanghai, China, May 13, 2020. The exhibition hall uses a large number of mirror devices, combined with the layout of acousto-optic, to create a visual scene and spatial effect. (Photo by Costfoto/Barcroft Media via Getty Images)

Exhausted grave diggers rest in between funerals at a cemetery designated for Covid-19 victims in Bandung on June 15, 2021, as infection numbers soar in Indonesia. (Photo by Timur Matahari/AFP Photo)

A Russian peacekeeper shouts “No pictures!” at a checkpoint outside the city of Stepanakert on November 13, 2020, during a ceasefire in the military conflict between Armenia and Azerbaijan over the breakaway region of Nagorno-Karabakh. Russian began deploying 2,000 peacekeepers to Nagorno-Karabakh on November 10 after Armenia and Azerbaijan agreed a peace deal to end weeks of fierce fighting over the disputed region. (Photo by Alexander Nemenov/AFP Photo)