The original cornerstone was laid in 1443, but the royal residence only began to take on its final form in 1701. Architect Andreas Schlüter designed the palace facades in the Italian style. With its 1,210 rooms, the City Palace subsequently became known as the biggest Baroque building north of the Alps.

During the Second World War the palace caught fire during an air raid. The fire destroyed virtually all of the state rooms in the north and south wing. Other parts of the building survived, including the outer walls with their sculptured decorations, the supporting walls, and the main stairwells.

Exhibitions were held in the post-war years in the surviving parts of the building. In 1950, however, the communist East German government decided it wasn't part of German cultural heritage and gave the order for it to be destroyed, despite many protests. In its place the Marx-Engels-Square was created as a location for mass rallies.

In the 1970s, East German leader Erich Honecker had the Palast der Republik built on the site. It became the seat of the East German parliament, but the building also served various cultural purposes as well as being home to numerous bars and restaurants. After the fall of the Berlin Wall the building was closed because of its asbestos content, and later torn down.

After German reunification, there was a passionate discussion about the possible reconstruction of the Berlin City Palace. In 1993, a pro-construction lobby group landed a coup by erecting a scaffold with a life-size canvas mock-up based on historical pictures of the City Palace façade. In 2002, the German parliament voted to have the palace reconstructed.

In 2008, the design by Italian Franco Stella won the architectural competition to rebuild the palace. His design combines the Baroque exterior with a more modern interior. The reconstructed Berlin City Palace is to house an international art and cultural center known as the "Humboldt Forum."

The "Humboldt Box" has become a temporary Berlin landmark - since 2011 it serves as an information center on the past and future of the City Palace. It attracted 100,000 visitors in the first 50 days alone. Visitors can also enjoy a panoramic look at how the reconstruction work is progressing from the viewing platform.

On June 12, 2013, German President Joachim Gauck laid the cornerstone, which has two numbers engraved on it: 1443 and 2013, the date when the cornerstone for the historical palace was originally laid and, of course, the date the reconstruction began.

While the walls are being constructed the Schlossbauhütte palace builders' shed, is making Baroque façade decorations. Using historic designs, sculptors are creating some 3,000 original pieces. The palace façade cost about 80 million euros ($90 million), most of which will be financed with donations. The finished palace will cost some 590 million euros, most of which will be financed by the state.

In 2016, gray concrete dominated the site - but this will change when the Humboldt Forum is opened. Then, Berlin Museums will exhibit their non-European cultural treasures here, while the Humboldt University begins holding international conferences. The Palace courtyard will serve as a backdrop for music and theater performances.

Though originally named the University of Berlin, in 1949 the name was changed to honor Alexander and his brother, Wilhelm, who helped found the school in 1810. Many Nobel Prize winners, among them Albert Einstein, have taught there. Today it is one of the country's best-rated universities and there is a statue of each brother in front of the main administrative building standing guard.

But Humboldt does not just belong to Germany. In Caracas, Venezuela, there is also a Universidad Alejandro de Humboldt, a private school founded in 1997. The country was the first stop in 1799 on Humboldt's journey through the Spanish American colonies. Today its second-highest peak is named in his honor. Located in the north-west of the country, it is near Pico Bolivar, which is the tallest.

It is fitting that Humboldt's name is mostly connected with nature or natural phenomenon — from China to New Zealand and Africa to Antarctica. In 1803, while sailing up the South American coast, Humboldt noted the cold water flowing north into more tropical waters. Though known to sailors and locals, he brought the current to a wider audience. It still impacts weather in Chile, Peru and Ecuador.

Yet Humboldt doesn't just belong on Earth. The explorer has a place on the moon. Mare, which means "sea" in Latin, is used to describe the mostly featureless plains on the Moon's surface. Humboldt's is one of only two named after a person. In reality though it is an oblong dark patch surrounded by more interesting impact craters. But don't worry, Humboldt has a crater, too — and two asteroids.

Back on Earth but still black and white is the Humboldt penguin, Spheniscus humboldti. The medium-sized flightless birds nest along the coast of Chile and Peru by burrowing in guano. Due to climate change, over-fishing and ocean acidification, they are endangered. The current population is estimated at a few thousand. In all it's thought that around 100 different animals are named after Humboldt.

But it's not just animals that share Humboldt's name, the naturalist is also namesake of around 300 plants. Some of the plants he discovered himself and brought back from South America like this deciduous tree, Salix humboldtiana. Yet even Humboldt was modest — of the thousands of specimens he collected, he only gave a handful of them his name. Other scientific fans named the rest in his honor.

A giant of science. A giant of trees. An appropriate name. Founded in 1921 the park is now the largest remaining old-growth forest of coastal redwoods, Sequoia sempervirens, and contains some of the tallest trees in the world. Across the American west, Humboldt is everywhere. In North America there are 4 counties, 13 towns and yet another university, Humboldt State Universtiy, named after him.

Though they look like they could be from outer space, the carnivorous Humboldt squid, Dosidicus gigas, lives for the most part in the Humboldt Current off of the South American coast. They usually move in large shoals, can change color quickly and reach a length of around 1.5 meters (4 feet 11 inches). But whereas Humboldt lived to be nearly 90, these marine animals only live 1-2 years.

Alas another fleeting thing named for Humboldt is the Humboldt glacier in Greenland. Its front is 110 kilometers (68 miles) wide, but it is melting fast. Due to climate change another Humboldt glacier in Venezuela has already nearly disappeared. In the past 30 years it has shrunk by 90 percent. Sadly it's the tropical country's last glacier; scientists only give it one or two more decades.

Back in his hometown the name Humboldt is being used to mark the future. Though controversial, the Humboldt Forum is scheduled to open this year in the newly rebuilt royal palace. No longer a king's house, it will be a cultural center and a museum for non-European art. Humboldt would feel at home, he spent time in the original palace and brought back some of the artifacts now going on display.