If you happen to live in the Northern Hemisphere, you may want to plan extensive activities to keep dad entertained this Father's Day. That's because June 21st happens to be the start of summer and the longest day of the year. Also known as summer 'solstice' - a Latin word for 'sun stands still', it is the day when the tilt of the Earth's semi-axis, in the northern hemisphere, is most inclined toward the sun.

Of course, the opposite is true for the residents of the Southern Hemisphere, who will be celebrating the shortest day of the year or winter solstice. So how long or short will your day be? That depends on where you live.

Alaska residents will receive between 19-22 hours of daylight, while those living in Washington DC will enjoy 15 hours. Across the Atlantic in London, UK the sun will shine for over 18 hours while in Sweden it will stay overhead for 22 hours. Those wishing to experience 24 hours of daylight will have to make their way to the Arctic Circle or the North Pole. Want to feel a day without the sun? Then head over to the Antarctica or South Pole where the sun will never rise.

Though we are now well aware that the extended day or night are a result of the Earth's tilt and rotation, ancient civilizations did not know this. They believed that the summer solstice was a sign that the sun had not abandoned them and, therefore, celebrated the event with elaborate festivals.

Stonehenge is one of biggest and oldest solstice celebrations in Europe (Credit: Stonehengetrips.com)

In North America, the Native American Sioux tribe paid their respects by setting up teepees in a circle to represent the cosmos. Members of the tribe would then dress in symbolic earth colors like red (sunset), blue (sky) and yellow (lightning) and stage spectacular dances to honor the energy-giving star.

One of Europe's biggest and oldest celebrations took place at Stonehenge in Wiltshire. Each year, thousands of people made their way to the stone structure that many believe was built to determine when the summer solstice would occur, to pay homage to the sun. This ancient tradition continues to this day.

In Ancient Greece, summer solstice marked the first day of the new year and was celebrated with several festivals. The most significant of them was in honor of agricultural god Cronus. Called Kronia it was the one time of the year when slaves were allowed to participate in the festivities with their masters as equals. The summer solstice also began the one-month countdown to the opening of the Olympic Games.

Though many of the old rituals have now been dispensed with, new ones have taken their place. In the Polish city of Poznan, St. John’s Night as it is called, is celebrated with the release of thousands of candle-lit paper lanterns that are adorned with personal messages from their creators. Since 2003, Japan has been staging "Candle Night" during both summer and winter solstice. As the name indicates, residents are urged to turn off all lights and electrical devices from 8-10 pm and encouraged to use candles to read a book or have a quiet dinner with loved ones.

In the beautiful coastal city of Santa Barbara residents celebrate the event with a three-day festival complete with parades that include large floats, extravagant costumes, and elaborate dances. In New York City, expert yogis and novices alike celebrate the summer solstice by perfecting their "downward dogs" at the "Mind over Madness" Yoga celebration in the city's bustling Times Square. In San Francisco, residents take advantage of the extra sunlight with storytelling and bonfire activities at the city's numerous beaches. Does your town or city have a fun summer solstice ritual? If so, be sure to tell us all about it, by adding your comments below.

Resources: Washingtonpost.com,wikipedia.org, huffingtonpost.com, ibtimes.com