(CNN) It's a pursuit nearly as old as the infamous shipwreck itself.

Divers first plunged into the waters off Nantucket, Massachusetts, to catch a glimpse of the Andrea Doria a day after the ship sank in July 1956. That first dive netted photos for Life magazine. Later, another expedition led to a documentary about the deadly shipwreck , which killed more than 50 people when the Italian luxury liner collided with another ship. For decades, the site became so popular with daring divers that it is known as "the Mount Everest of wreck diving."

Officials have long warned that it's a dangerous dive to get to the shipwreck site, 240 feet underwater. In the past decade alone, the Coast Guard says , seven people set out to reach the wreck and never returned.

Another diver went missing this week and is presumed dead. The Coast Guard said it suspended the search for the missing 64-year-old man Wednesday night and notified his next of kin.

The diver was last heard from on Tuesday while diving about 60 nautical miles southeast of Nantucket, the Coast Guard said.

Another diver reported that he'd been with the man underwater, but didn't see him when he got back to the surface.

Coast Guard crews -- by air and by sea -- searched more than 350 square nautical miles over 30 hours as they looked for a sign of the missing diver before announcing the search had been called off.

It was a difficult decision, a top official said.

"The primary goal of every man and woman who serves in the Coast Guard is to rescue those in need and save lives," said Marcus Gherardi, chief of response at Coast Guard Sector Southeastern New England. "This is why we serve. It is extremely disheartening anytime we are unable to accomplish this goal."

The shipwreck site is a popular destination for advanced divers and charter services that bring people to the area, Coast Guard spokeswoman Lt. Karen Kutkiewicz said. But given how deep it is, she said, it's not an appropriate spot for recreational divers.

The risky trek has become so notorious that it was the topic of a 2002 book, "Deep Descent: Adventure and Death Diving the Andrea Doria."

In the book's foreword, author Kevin F. McMurray says the ship's mystique draws people into the depths of the Atlantic: "her untimely demise, the tragic loss of life, the rescue of her survivors by her heroic brethren, and of course the whims of the open oceans that brought about her destruction."

Why risk it?

"As someone who remembers her dramatic sinking and yearns to keep a piece of that precious time close to heart," he says, "I can think of no more fitting tribute than beholding the magnificent lady up close and touching her now silent remains, and maybe if lucky and bold enough even bringing back some artifact from her to preserve and display."

But Coast Guard officials offered more words of warning in their statement on this week's missing diver.

"The ocean is unforgiving," the statement said. "The Coast Guard reminds everyone on the water, whether diving, snorkeling, boating or swimming to stay vigilant, especially in unfamiliar places."