Spend an hour or two ambling through the Great Lakes Science Center's "Chocolate: The Exhibition," now through May 4, and you'll never look at a candy bar the same way again.The museum's lower level space offers an artful exploration of more than a millennium of chocolate - from its origins in the rainforests of Central America to its $13 billion in annual sales as America's favorite snack. Along the way you'll meet the Mayans and the Aztecs, who drank their chocolate in its natural bitter state and so valued the seeds of the cacao (pronounced kah-kow) tree that they used them as money.It's appropriate, given its Central America origins, that the exhibit is completely bilingual, with Spanish as its second language.The Candy Bar - where science meets the sweet treat - will give a close-up look at what's involved in making chocolate. There you can even test your taste buds to see if you are a super taster - someone who experiences taste with above-average intensity. That interactive part of the touring exhibit was created just for Cleveland visitors.It's no coincidence that the exhibit will be in Cleveland for both Valentine's Day and Easter, the times when people are most interested in chocolate. And a dedicated gift shop, brimming with chocolate creations from near and far, will most certainly become a popular shopping stop.Linda Abraham Silver, executive director of the Great Lakes Science Center, has long wanted to bring "Chocolate: The Exhibition" to Cleveland. She first experienced it when she was vice president of education and guest relations at the Natural History Museum of Los Angeles County.The show came most recently from Chicago, but those who saw it at the Field Museum might not recognize "Chocolate" in its Cleveland incarnation. It's been completely reconfigured and, of course, includes the addition of the Chocolate Bar. "Not only is it a lot of fun, the exhibit is thought-provoking and steeped in historical facts that will interest the entire family," Abraham Silver said. Shortly after entering, seeing becomes believing. A fake cacao tree has its pods directly on the tree trunk - just as they are in nature. They grow that way so the minuscule midges that live on the forest floor and pollinate the seeds can better reach them.Each pod contains hundreds of seeds that were fermented, dried, roasted and crushed by Mayans living 1,500 years ago. They added water and spices to the concoction, which they drank and used as a sacrifice to their gods.The botanical name for the cacao tree - Theobroma Cacao - even translates as "Food for the Gods."The exhibit's initial displays are framed in deep green foliage to represent the rain forest. Backdrops segue to replicate murals from the ancient Aztec and Mayan civilizations.Descendants of those early Mayans who live in Chiapas, Mexico, still use chocolate as a sacred offering to this day. And chocolate in Mexico - as well as in Spain - still remains more popular as a drink than as a candy.When the Spanish began to colonize Mexico, they were intrigued with the Aztecs' frothy chocolatl drink, to which the natives added corn to make a porridge. The conquistadors brought chocolate back to Spain, where it was embraced by the upper classes, who added sugar and vanilla to the beverage for the first time. The Aztecs considered chocolate sacred and believed drinking it bestowed wisdom. The Europeans considered it to be an aphrodisiac, so it became wildly popular. One exhibit shows that more than 12 million pounds of chocolate was consumed in Europe between 1759 and 1789 - an astonishing statistic with the realization that all of it had to come by ship from Central America.Like many objects of human desire, the love of chocolate had its despicable side. Indians were enslaved to harvest cacao by hand while African slave labor was used to fill the demand for sugar to mix with chocolate. Even today, when most of the world's chocolate is grown on Africa's Ivory Coast, child labor is used to harvest and prune the cacao trees.One entire wall of the exhibit tells the story of chocolate on TV monitors - made to look like square chocolates in a chocolate box filled with candies the same size. Visitors sit on cushions that look like chocolate pieces, each embraced by pleated bon-bon papers.The Science Center's Lou Palermo conducts a chocolate tasting in the Chocolate Bar, encouraging tasters to discern the fruitiness and intensity in the initial taste and the earthy, floral, woody, tobacco and other notes the emerge as the chocolate melts on the tongue. "Good chocolate has a clean, clear taste," she said. "Fats should clear the mouth quickly, leaving the strength of the flavor behind."Great chocolate should leave its taste in the mouth up to 30 seconds after it's been consumed."Pin holes indicate air bubbles," she said. "And a dark glossy shine indicates it's been properly tempered."The gift shop at the conclusion of "Chocolate: The Exhibition" may seem mind-boggling in its breadth and content. Despite being part of the exhibit itself, it can be visited separately. There you'll find chocolate from all over the world, including chocolates with chilies, wasabi, bacon and cherries. Chocolate-themed books, puzzles and games can be a sweet treat for young and old. There's even a slightly naughty chocolate body frosting, sold with a brush.