Today is National Hamburger Day in the United States, and Connecticut is home to where this American culinary icon served between bread was born. In 1900 at Louis\u2019 Lunch in New Haven, Louis Lassen created the first hamburger sandwich for a customer who needed an item to go, long before the drive-thru window. Hand grinding some beef and placing it between two slices of toast, a legend was born. May 28 is National Hamburger Day. \u201cThe humble hamburger is a staple of western culture,\u201d according to publicity material. \u201cBurger joints, takeaway food outlets and all-night-eateries serve them up in their millions.\u201d Library of Congress documentation Documented by the Library of Congress as the birthplace of the hamburger sandwich (a hamburger inside bread, a bun or a roll), the original process remains unchanged at Louis\u2019 Lunch. Burgers still are grilled in the original vertical cast-iron grills dating back to 1898. And keeping with tradition, the only toppings are cheese, tomato and onion. Not on the menu are ketchup, mustard and mayonnaise. \u201cThe Lassens remain committed to the belief that the beef speaks for itself,\u201d according to Visit New Haven, the city\u2019s tourist bureau. Some other locations in the United States also claim to be the birthplace of the hamburger sandwich. \u2018Truly a national treasure\u2019 Ginny Kozlowski, executive director of Visit New Haven, said Louis\u2019 Lunch is a popular place to visit in the Elm City. \u201cThe first question out of many visitors\u2019 mouths is, \u2018Where is Louis Lunch?\u2019\u201d Kozlowski said. \u201cWith national and international media coverage and worldwide acclaim, Louis\u2019 is truly a national treasure.\u201d For anyone planning a visit, Louis\u2019 Lunch at 261-263 Crown St. in downtown New Haven is open Tuesday and Wednesday from 11 a.m.-3: 45 p.m., and Thursday to Saturday from noon-2 a.m. It is closed Bring cash, because credit and debit cards are not accepted. The eatery is traditionally closed during the month of August, with the dates this year being Aug. 3 to Sept. 1.