(CNN) — Call it love. Call it romance. Call it sensuality. Go ahead and call it old-fashioned lust if you want.
But whatever you call it, the summer solstice for 2020 is arriving -- and it has a history of stirring hearts and libidos.
The longest day of the year in the Northern Hemisphere kicks off the official start of summer and with it, the bounty of the harvest.
So it should come as no surprise that the solstice is linked to fertility -- both of the plant and human variety -- in destinations around the world. CNN Travel explores some of those long-standing summer traditions. But first, we'll take a look at the science of a solstice and what's special in 2020.
Summer solstice: Q&A
Question: I like precision. Exactly when is the summer solstice in 2020?
It will happen at 21:43 UTC (Universal Coordinated Time) on Saturday, June 20. If you're in the Eastern Time Zone of the United States, that's 5:43 p.m. June 20.
But if you happen to live in Tokyo, for instance, your precise summer solstice moment actually happens at 6:43 a.m. on Sunday, June 21.
In fact, all of Asia will observe the solstice on June 21. Berlin, Germany, in Central Europe barely falls on the June 20 date at 11:43 p.m. local time.
Question: It's the longest day of the year -- and it happens all over the world?
Nope. It's the longest day only in the Northern Hemisphere. It's the shortest day of the year south of the equator. They are about to welcome three months of winter there.
An old-fashioned tall ship sails on the Neva River in St. Petersburg on the early morning of June 24, 2017. Residents of the city celebrate their many hours of daylight and nights that don't get fully dark this time of year with the White Nights Festival.
Sergey Mihailicenko/Anadolu Agency/Getty Images
And the differences in how much daylight you get become very dramatic as you get closer to the poles and farther from the equator. For instance, residents of northerly St. Petersburg, Russia, will get a 3:35 a.m. sunrise and almost 19 hours of light. Even the night doesn't get that dark.
In Singapore, a Northern Hemisphere city-state but one just barely above the equator, people barely notice the difference. They get a measly extra 11 minutes of daylight.
As for those poor penguins in Antarctica guarding their eggs -- if they could talk, they could tell you a lot about living in 24-hour darkness.
This NASA photo shows the summer solstice from 2018. Notice the angle of the terminator (the line between day and night). This tilt exposes the Northern Hemisphere to more direct sunlight than the Southern Hemisphere.
Question: Why don't we just get 12 hours of daylight all year?
Folks all over the planet actually did get equal doses of day and night back during the spring equinox on March 20. But the amount of sunlight we get in the Northern Hemisphere has been increasing daily ever since. Why?
"As Earth orbits the sun [once each year], its tilted axis always points in the same direction. So, throughout the year, different parts of Earth get the sun's direct rays," according to NASA.
When the sun reaches its apex in the Northern Hemisphere, that's the summer solstice.
At that time, "the sun is directly over the Tropic of Cancer, which is located at 23.5° latitude North, and runs through Mexico, the Bahamas, Egypt, Saudi Arabia, India and southern China," according to the National Weather Service.
Bonus for 2020: Annular eclipse
It's going to be a really big celestial weekend for some people in the Eastern Hemisphere. In addition to the solstice, they will get to witness an annular eclipse. (Using proper eye protection, of course).
On Sunday, the new moon will pass between the Earth and the sun, blocking it out minus a fiery ring on the edges. An annular eclipse differs from a total eclipse, in which the entire sun is blocked. A new moon is simply too far away from Earth to completely obscure the sun's disc in an annular eclipse.
People in the Western Hemisphere will just have to settle for a good solstice as it will be nighttime in their part of the world when the annular eclipse occurs.
Sensual traditions: Midsummer in Sweden
Who says traditions can't be mixed? This Midsummer celebration from 2017 has traditional Swedish dances but also Bollywood music and dance in Folkets Park, Malmö, a city with a diverse population.
Lindholm/Pacific Press/LightRocket/Getty Images
But let's turn our attention to what's really on our minds -- the romance of the solstice. We'll start in Sweden.
Their traditions include dancing around a maypole -- a symbol which some view as phallic -- and feasting on herring and copious amounts of vodka.
"A lot of children are born nine months after Midsummer in Sweden," Jan-Öjvind Swahn, a Swedish ethnologist and the author of several books on the subject, told CNN before his death in 2016.
"Drinking is the most typical Midsummer tradition. There are historical pictures of people drinking to the point where they can't go on anymore," said Swahn.
While the libations have a hand in the subsequent baby boom, Swahn pointed out that even without the booze, Midsummer is a time rich in romantic ritual.
"There used to be a tradition among unmarried girls, where if they ate something very salty during Midsummer, or else collected several different kinds of flowers and put these under their pillow when they slept, they would dream of their future husbands," he said.
Pagan rites in Greece
There is a similar mythology about dreaming of one's future spouse in parts of Greece. There, as in many European countries, the pagan solstice got co-opted by Christianity and rebranded as St. John's Day. Still, in many villages in the country's north, the ancient rites are still celebrated.
One of the oldest rituals is called Klidonas, and it involves local virgins gathering water from the sea.
The village's unmarried women all place a personal belonging in the pot and leave it under a fig tree overnight, where -- folklore has it -- the magic of the day imbues the objects with prophetic powers, and the girls in question dream of their future husbands.
The next day, all the women in the village gather, and take turns pulling out objects and reciting rhyming couplets that are meant to predict the romantic fortunes of the item's owner. These days, however, the festival is more an excuse for the community of women to exchange bawdy jokes.
"In my village, the older women always seem to come up with the dirtiest rhymes," says Eleni Fanariotou, who has filmed the custom. Later in the day, the sexes mingle and take turns jumping over a bonfire.
Anyone who succeeds in jumping over the flames three times is meant to have a wish granted. Fanariotou said the festival often results in coupling.
"It's a good time to meet someone, because all the young people in the village go, and it's a good opportunity to socialize. Plus, all the men like to show off, and make the biggest fire they can to jump through."
Yoga in India
Few things get you in touch with your mind -- and your body -- like yoga does.
In India, where they definitely know their yoga, the summer solstice is traditionally celebrated with mass yoga sessions.
Indian yoga practitioners take part in a session on International Yoga Day in 2019 at the 15th century Adalaj Stepwell in Adalaj, in western Gujarat state. For 2020, people in India are being urged to do their yoga at home with families.
Sam Panthaky/AFP/Getty Images
In fact, the International Day of Yoga is June 21, the same day as the solstice in India.
Like many other things in 2020, this year will be different because of the coronavirus pandemic.
A Slavic Cupid
In Eastern Europe, solstice celebrations fall on Ivan Kupala Day -- a holiday with romantic connotations for many Slavs ("kupala" is derived from the same word as "cupid"). In 2020, Ivan Kupala Day starts on the evening of July 6 and ends of the evening of July 7.
"It was once believed that Kupala night was a time for people to fall in love, and that those celebrating it would be happy and prosperous throughout the year," recalls Agnieszka Bigaj from the Polish tourist board.
It used to be that young, unmarried women would float floral wreaths in the river where eager bachelors on the other side would try to catching the flowers. she adds.
According to Polish folklore, the man and woman in question would become a couple. Bonfires are also a large feature of the holiday, and it's tradition for a couple to leap through the flames together while holding hands -- if they don't let go, it is said their love will last.
One of the largest annual solstice celebrations in the world takes place at Stonehenge in England, where thousands usually gather each year. Like many other events in 2020, it's having to alter traditions because of the pandemic.
While the usual in-person gathering is on hold, you'll be able to live stream sunset on June 20 and sunrise on June 21 at the site of these precisely arranged giant stones on English Heritage's Facebook page. Talk about a short night. The June 20 sunset is at 9:26 p.m. local time, and sunrise will start at a very early 4:52 a.m. local time, so be sure use an online time zone converter if you want to watch either or both.
Dating back to druid and pagan times, Stonehenge has allure.
"All druid rituals have an element of fertility, and the solstice is no exception," King Arthur Pendragon, a senior archdruid, told CNN.
"We celebrate the union of the male and female deities -- the S\sun and the Earth -- on the longest day of the year."