"Throughout its history, the story of Fort Matanzas has been closely intertwined with that of the city of St. Augustine and the Castillo de San Marcos. This Spanish outpost fort was built in 1740-1742 to guard the Matanzas Inlet and to warn St. Augustine of British or other enemies approaching from the south. Fort Matanzas now serves as a reminder of the early Spanish empire in the New World.

According to the National Park Service, "In the northwest corner of Fort Vancouver's protective palisade wall, a three-story tower called a bastion or blockhouse rose above the surrounding plain. From the top, Hudson's Bay Company (HBC) employees could keep watch over the Columbia River valley and its gently rolling hills. The bastion was a common feature of HBC posts throughout North America.

"Only from an aerial view can the entire breadth of Fort Monroe [National Monument] be taken in all at once. Consisting of many significant examples of historic, cultural, and natural resources the almost 600 acres of Fort Monroe, VA has been a National Historic Landmark since 1960."

According to the National Park Service, "Fort Pulaski National Monument is located in Georgia and was added to the Network in 2019. Fort Pulaski National Monument was captured by US forces in the Spring of 1862, an event which served as the impetus for General David Hunter to issue a series of orders formally emancipating the enslaved people of coastal Georgia and South Carolina. The fort was later garrisoned by United States Colored Troops in 1866."

"F" is for "Fort" and all the forts and their history preserved as or within units of the National Park System.

According to the National Park Service, "In November 1805, the Corps of Discovery reached the Pacific Ocean. Having found 'the most practicable and navigable passage across the Continent of North America,' the mission was complete. Although eager to begin the journey home, members of the Corps knew that travel would have to wait until spring - more than one snowy mountain range stood in their path. The Corps would build a temporary home on the coast."

"About 1.2 million years ago, a spectacular volcanic eruption created a 13-mile-wide circular depression in the earth now known as Valles Caldera. The preserve is known for its huge mountain meadows, abundant wildlife, and meandering streams. The area also preserves the homeland of ancestral native peoples and embraces a rich ranching history."

"High ancient sea ledges, deep rocky canyons, flowering cactus, and desert wildlife—treasures above the ground in the Chihuahuan Desert. Hidden beneath the surface are more than 119 caves—formed when sulfuric acid dissolved limestone leaving behind caverns of all sizes."

"Wind Cave National Park protects two very different worlds - one deep within the earth, the other a sunlit world of many resources. Bison, elk, and other wildlife roam the rolling prairie grasslands and forested hillsides of one of America's oldest national parks. Below the remnant island of intact prairie sits Wind Cave, one of the longest and most complex caves in the world."

How about those trees! Taller than tall, "A forest with giant sequoias, the largest trees in the world, is a feast for the senses. The giant sequoias’ red/orange bark is distinct among the grey and brown bark of other trees. And if you stand beneath one of these giants, you can gaze all the way up its tall trunk and through its high branches to see sky above. The treetop is often hidden above the highest branches.

Who says geology is boring or dull? "Dinosaurs once roamed here. Their fantastic remains are still visibly embedded in the rocks. Today, the mountains, desert, and untamed rivers flowing in deep canyons support an array of life. Petroglyphs hint at earlier cultures. Later, homesteaders and outlaws found refuge here."