If you live in the Northern Hemisphere, June 21st may seem like a day when the sun has forgotten to set and depending on where you live that may actually be true, because today happens to be not just the first day of summer, but also, the longest day of the year!

Known as the summer 'solstice' - a Latin word for 'sun stands still,' it is the day when the Earth's axis is most inclined toward the sun and except for leap years always occurs on June 21st. Countries in the Southern Hemisphere experience a similar phenomenon, except in reverse order - Today is the first day of winter and therefore the shortest day of the year, while December 21st, will be the longest, marking their first day of summer.

The amount (or lack of) sun received during this day, depends on the location of your city or town. Washington D.C. on the east coast of United States will receive almost 15 hours, while the islands of Hawaii in the southwest corner of the country will have to settle for just a tad over 13. Head over to Europe and you will be able to soak in over 18 hours of sunshine in London or more than 21 hours in Stockholm. The best place to be, however, is north of the Arctic Circle where the sun will not set at all! Conversely, the Antarctica or South Pole will not see any sunlight today.

Though we now realize the cause of this extended day, ancient cultures regarded it as a spiritual occasion and celebrated it with joyous rituals - Some of which continue till today. One of the oldest and biggest celebrations takes place at Stonehenge in Wiltshire, England where thousands of people gather each year, to pay homage to the rising sun. The Swedes celebrate the day with a week-long festival, while the people of Poland leap over bonfires to ward off evil spirits.

Modern day rituals include Japan's Candle Nights a two-week event to help the environment. Started in 2003, it encourages people all over the world to turn off lights (and all electrical devices) from 8.00 pm to 10 pm every single day, for the entire fortnight.

New York City celebrates the first day of summer with 'mind over madness' Yoga - A free, open for all event where the only requirement is a yoga mat and the desire to sit in awkward poses in the middle of the bustling Times Square. In the beautiful coastal city of San Francisco, the day is celebrated with storytelling, songs, and bonfires at a number of the city's local beaches. Does your town or city have a summer solstice ritual? If so, be sure to let us know by adding your comments below.

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