The death knell has tolled for the Big Mac.

Only one in five millennials, aged 18 to 34, has ever tried or knows what a Big Mac tastes like, according to The Wall Street Journal.

The burger, comprised of two beef patties, special sauce, American cheese, pickles, onions, and lettuce served on a three-part sesame seed bun is becoming less relevant among consumers as they frequent chains that make fresher options, such as Shake Shack and Smashburger.

McDonald’s, seeing an opening in the “fresh” burger market, is testing fresh instead of frozen beef, different cooking techniques, and customized ordering options for “made-to-order” burgers.

Customers can choose a type of meat, bun, and toppings, such as guacamole or bacon.

But the chain has to deal with the challenges of keeping its speedy service, value, and business afloat.

The chain’s global sales plummeted 2.3 percent and declined 2.6 percent in the U.S. for the first three months of 2015, according to the Daily News.

In 2014, a Consumer Reports taste survey of 21 burger chains ranked McDonald’s last. Survey participants called them the “worst tasting of all the major U.S. burger chains.”

In recent years, business has suffered compared to other fast food outlets because of consumers perceiving the food as unhealthy for its high fat, sodium, and calorie counts.

Once in its heyday, McDonald’s restaurants in 66 countries have sold 14 billion Big Macs in 13,000 of its restaurants since its creation, the Daily News reported.

The burger was created by Jim Delligatti in a suburb north of Pittsburgh in 1967 before it hit McDonald’s nationwide a year later.  The original starting price? Forty-seven cents.

Today, Big Macs cost around $4.29, a little less than the cost of a ShackBurger from Shake Shack at $6.84.