Here are five fun national days to celebrate on September 15, 2025:

1. National On-Line Learning Day (September 15)
   • History: Founded in 2016 by the Online Learning Consortium, this day recognizes and celebrates the profound impact and growing importance of online education. It highlights the flexibility, accessibility, and innovation that online learning brings to students worldwide.
   • Relevance: In today’s digital age, online learning has become a fundamental part of education, from K-12 to higher education and professional development. This day acknowledges the transformative power of virtual classrooms and the opportunities they create for lifelong learning.
   • Celebration Ideas:
     • Explore a new online course or tutorial on a subject that interests you.
     • Thank an online educator or mentor who has impacted your learning journey.
     • Share your positive experiences with online learning on social media using #OnlineLearningDay.
     • Learn about new technologies and platforms that are enhancing virtual education.
2. National Greenpeace Day (September 15)
   • History: This day commemorates the founding of Greenpeace in 1971. A group of activists set sail from Vancouver, Canada, to protest nuclear testing in Amchitka, Alaska. Their courageous act marked the beginning of one of the world’s most influential environmental organizations.
   • Relevance: National Greenpeace Day highlights the ongoing need for environmental advocacy and action. It encourages individuals to reflect on critical ecological issues, from climate change to biodiversity loss, and to support efforts aimed at protecting our planet.
   • Celebration Ideas:
     • Learn about current environmental challenges and solutions.
     • Support a local or international environmental organization.
     • Reduce your own ecological footprint by conserving energy and minimizing waste.
     • Share information about environmental issues and solutions on social media using #GreenpeaceDay.
3. National Double Cheeseburger Day (September 15)
   • History: The cheeseburger itself gained popularity in the 1920s and 30s. The “double” version simply doubles the deliciousness, offering more meat and cheese for burger enthusiasts. This day is an informal celebration of this hearty American classic.
   • Relevance: The double cheeseburger is a quintessential comfort food and a staple of American cuisine. This day offers a fun excuse to indulge in a satisfying meal and celebrate a beloved culinary creation.
   • Celebration Ideas:
     • Order a double cheeseburger from your favorite restaurant.
     • Grill up your own double cheeseburgers at home with all your preferred toppings.
     • Experiment with different cheeses and gourmet toppings for your burger.
     • Share a photo of your delicious double cheeseburger on social media with #DoubleCheeseburgerDay.
4. National Crème de Menthe Day (September 15)
   • History: Crème de Menthe is a sweet, mint-flavored liqueur that originated in France. It is typically green, though a clear version also exists, and is used in a variety of cocktails and desserts. This day celebrates this refreshing and versatile liqueur.
   • Relevance: This day is a fun opportunity to explore the world of liqueurs and classic cocktails. Crème de Menthe is a distinctive ingredient that can add a unique minty flavor to drinks and sweet treats.
   • Celebration Ideas:
     • Try making a classic cocktail like a Grasshopper or a Stinger using Crème de Menthe.
     • Add a splash of Crème de Menthe to your hot chocolate or coffee.
     • Experiment with a dessert recipe that incorporates Crème de Menthe, such as mint chocolate chip ice cream or a minty fudge.
     • Share your minty creations on social media using #CremeDeMentheDay.
5. National Felt Hat Day (September 15)
   • History: Felt hats have a long history, dating back thousands of years. From fedoras and trilbies to cowboy hats and bowler hats, felt has been a popular material for headwear due to its durability and moldability. This day celebrates the style and tradition of felt hats.
   • Relevance: Felt hats remain a timeless fashion accessory, offering both practicality and elegance. This day encourages people to embrace this classic headwear and appreciate its history and versatility in personal style.
   • Celebration Ideas:
     • Wear your favorite felt hat throughout the day.
     • Learn about the different styles and history of felt hats.
     • Shop for a new felt hat to add to your wardrobe.
     • Take a stylish photo wearing your felt hat and share it on social media with #FeltHatDay.