The Leaning Tower of Pisa receives over 1 million visitors per year. The tower is part of Cathedral Square made up of the Pisa Cathedral, Pisa Baptistery, and the Piazza del Duomo.

Problems with the tower started shortly into its construction. The soft soil in Pisa caused the tower to start leaning once construction reached the second story. It would continue to get worse until a renovation project stabilized the tower in 2008. Previous attempts had been unsuccessful, and had even made it worse. Today, the tower sits at 3.97 percent angle.

You can climb to the top of the tower to experience the views of the surrounding city. 296 stairs will take you to the top. Tickets can be purchased in advance.

Starting today, the Leaning Tower of Pisa can be added to your Duckwyn Passport book. 

Today, Leonardo da Vinci was added to the list of historical people for you to find and collect. If you're visiting Milan, check out Leonardo da Vinci's famous painting of The Last Supper. Nearby, use your Duckwyn Passport app to find out more information on the unique painting style he used to improve the detail and luminosity of the painting.

If you want to see Da Vinci's painting of The Last Supper, make sure you buy tickets ahead of time. They sell out quickly even in the off-peak months. Use this official reservation site when buying tickets.

The Cattedrale di Santa Maria del Fiore took over 140 years to complete. It's the 3rd largest church in the world. But, it didn't take that long to build because of its size. It took 140 years to build because no one knew how to construct the domed rooftop.

In 1418, over 120 years after the first stone was laid, Florence held a competition to find someone who could successfully build the domed rooftop from the original design. For years, the cathedral remained mostly complete with the exception of it's open roof where the dome would go. The citizens of Florence grew frustrated but they didn't want to change the design. The wanted the work completed so they could show off their grand design and stand out from the surrounding cities. They hoped that the competition would find someone who could find a way to get the job done.

A goldsmith by the name of Filippo Brunelleschi won the competition despite having no prior construction experience. His unique brick herringbone design was simpler and more cost effective than the other solutions. Brunelleschi's design used gravity to his advantage. The interlocking brick design was extremely strong, allowing him to build a dome that would last for centuries. Today, you can visit the cathedral and climb to its rooftop. On your way, be sure to take in Brunelleschi's genius design.

While you're visiting, be sure to use your Duckwyn App to collect your virtual stamp and coin. 

Ponte Vecchio is the oldest bridge in Florence. It opened in 1345 and its been a bustling shopping area ever since. Fishmongers, tanners, and butchers have had shops here since the 13th century. Today, it is still a lively spot for tourists to enjoy the views and to visit the local shops. Remarkably, the bridge managed to survive World War II. When all the other bridges were bombed and destroyed to slow the advancing allied forces, Ponte Vecchio remained intact. It is believed that Adolf Hitler found the bridge too beautiful to destroy.

Starting today, you can add Ponte Vecchio to your Duckwyn Passport.

The Empire State Building was a marvel built in the 1930's. It was designed, planned, and built in just 20 months and would be the tallest building in world until the World Trade Center's North Tower surpassed it in 1970. 

The Empire State Building was originally going to have just 50 stories but in the end it soared to 102. In the late 1920's, the Chrysler Building was being constructed, and its designers wanted it to surpass the height of the planned Empire State Building. Both would try to surpass each other with taller designs but in the end, the Empire State Building would win out. It's final height is about 200 feet taller than the Chrysler Building.

Today, you can visit the 86th and 102nd floors to get 360 degree views of New York city. You can purchase tickets ahead of time to avoid the lines. While visiting, be sure to use your Duckwyn app to add your stamp.

Castello Sforzesco in Milan has evolved over the years. It was built in 1450 by Francesco Sforza, Duke of Milan, as his residence. When he died, his son Galeazzo Maria continued its construction. In the late 1400’s, Ludovico Sforza became Lord of Milan and hired many artists including Leonardo da Vinci to decorate the castle. Leonardo’s work can seen on the ceiling of the Sala delle Asse.

When the Spanish controlled Milan in the 1500’s, they converted the castle to a citadel. They modernized the castle fortress by changing its design and extending the walls.

In the early 1900’s, when Italy became unified, the castle was no longer used by the military. Instead, it was used by the city. The government of Milan continued the restoration work. The Via Dante was built to connect the castle to the Duomo.

Today, the castle has become a collection of museums. These museums include the Museum of Ancient Art, the Museum of Musical Instruments, the Egyptian Museum, the Architectural Museum of Milan, Applied Arts Collection, the Antique Furniture & Wooden Sculpture Museum, the Pinacoteca del Castello Sforzesco, the Achille Bertarelli Print Collection, and the Museum of Rondanini Pietà.

Starting today, you can visit Castello Sforzesco and use your Duckwyn Passport to add the stamp to your collection.

Sacré-Coeur was built as a symbol of penance for years of bloody battles between the France and Germany, and the Vatican. Ironically, the basilica was completed in 1914, the same year that World War I would begin. 

The basilica stands on top of the highest point in Paris at the summit of Montmarte. The stunning view of the city is complemented by the equally beautiful, white stoned church. Sacré-Coeur is located away from many of the other tourist attractions but if you have the time, it's worth the Metro ride over to explore this part of Paris.

Sacré-Coeur is the second most visited monument in Paris so it can get busy. If you walk through the park below, be warned that there are usually very aggressive souvenir sellers looking for an opportunity to slap a bracelet on your wrist and then follow you around until you pay them. This can detract from the park a bit but if you're aware of this ahead of time, you can avoid these situations and still enjoy your experience.

Sacré-Coeur is now included in your Duckwyn passport. If you don't have one yet, get yours for free while we're still in beta.

Visit the Sistine Chapel and see one of the most difficult, yet one of the most beautiful paintings in the world. Michelangelo created this remarkable painting between 1508 and 1512 while lying on his back. It took a great physical toll on him. Michelangelo considered himself more of a sculptor and this comes through in his painting. The figures that cover this enormous painting share the same beauty and strength as you would see in a sculpture.

In addition to seeing Michelangelo's painting, you'll be visiting one of the most important locations within the Vatican. It is here that popes are chosen and crowned. When a new pope is being chosen, smoke signals are used to alert the world of the status of a new pope. Black smoke means that they haven't found a Pope. White smoke is used when a new Pope has been found.

Over the past year we've been adding over 50 historical sites, 18 different historical people, 50 US State Capitals, and several general points of interest to help families discover and learn about world history. Today, you can view them on our free trip planning tool.

We want to make it easy for you to plan your day ahead of time. The planner allows you to select what you want to see and the order you want to visit them. The map will adjust to show you the best path to each of the sites. You can then use the Duckwyn Travel app to learn about and track each of the places you go.

Additional features for Duckwyn Passport subscribers

If you have an account, you will also be able to add your own points of interests. So if there's a restaurant you want to stop in for lunch or a park you want to take a break and let the kids run around in, you can add them to your itinerary too.

More historical sites are coming soon. Check the free city tour planner today and let us know what you think.

On this day, 100 years ago, Congress passed the 19th Amendment giving women the right to vote. Susan B Anthony and Elizabeth Cady Stanton worked tirelessly during the mid to late 1800's to clear the path for this new law. Together, they campaigned for women's rights and for the rights of African Americans. Neither would live long enough to see the 19th amendment passed but there's no doubt about the importance of their work.

Starting today, you can find Susan B Anthony's Duckwyn card near her home, and now museum, in Rochester, New York.