For me it was the Book of Kells in Trinity College in Dublin. Well I saw two of the four volumes. And I suppose the library itself was outstanding.
What are you glad you have seen?
Stonehenge and the stone circles at Avebury.
Andres Segovia at the Academy of Music (he was a relic in 1978, believe me)
The Alhambra in Granada, Spain
The Pennsauken Mart (local NJ color, now gone)
Veterans’ Stadium in Philadelphia
The Liberty Bell when it was still in Independence Hall
It means very little now, only 7 years on,
but in 50 years I’ll be able to tell people all about watching the attack of 9-11 unfold on Sky and BBC news 24.
And then talk about what happened to the world in the following years/decades.
But things that I’ve actually been to see… there aren’t many. None that spring to mind.
I’ve held and flipped through a first edition, autographed copy of Tristram Shanty by Laurence Stern, from around 1760.
Anyway, it was in good shape(multiple volumes) and was really cool to flip through. The illustrations were hand colored and the text was perfectly readable.
The King Tut exhibit that toured Los Angeles a few years back.
Not really a relic, but I saw an iceberg once. 300 feet long, 150 feet showing above water (probably at least 700 below). We sailed by in a tiny boat, about 100 feet from the bergs base. Most amazing thing I’ve ever seen.
Some of the Dead Sea Scrolls went on tour and were here in San Diego last year. I went to that, and it was pretty cool. I mean, when am I ever going to see that again? I’m not sure that I’m ever going to make it to that part of the world…
The step-pyramid at Saqqara, the Great Pyramids and Sphinx at Giza, and the Valley of the Kings, from a trip to Egypt 24 years ago. The Pyramid, Ball Court and other things at Chichen Itza in Mexico, more recently.
The Winged Victory of Samothrace at the Louvre–30 years ago now.
That I had been to the top of the World Trade Center, both the observation deck, and the Windows on the World restaurant.
I will be glad that I attended baseball games at both Shea and Yankee Stadiums, once they are gone.
Too many things to count, or even remember in detail right now, at the Metropolitan Museum of Art in NY, where I used to work.
My little brother, who was ten at the time and whom we knew to have the imagination and creative spirit of a brick, looking at the view from the Alhambra and saying “wow, now I know why they fought so hard for this place!”
The Alcázar in Segovia.
The chains and emerald (it’s a “mother emerald”, really, a lesser stone with tiny emeralds embedded inside) which Sancho VII brought as a souvenir from the battle of Las Navas and which now are my homeland’s coat of arms.
The view from the top of WTC.
It wasn’t a relic, but the meeting with JPII at Santiago was pretty powerful stuff and a lot of fun. The moment where I’ve felt more as part of a “Universal” Church (that’s what the word “Catholic” means) was at Mass in Athens, though: there were less than two dozen people there, and we said the Lord’s Prayer in at least 8 different languages.
I second the Book of Kells and Stonehenge, and add:
– the Pompeii volcano site
– Pope John Paul II at the Vatican (even though he was just a small white figure on a faraway platform)
– my great-great grandfather’s grave in Ireland
– Altun Ha in Belize
I also second Veterans Stadium and Yankee Stadium. 
I was one of the first “regular guys” to see Lucy when she came to Houston last year. Houston is the first stop on a multi city US tour, so lots of other people will be able to see her.
She is not displayed in Ethiopia, they keep her locked up and have a replica on display.
Sigmund Freud’s home in Vienna.
I’ll second the WTC. I went to the top in May of 1991, and I still have my ticket stub.
Biltmore House in Ashville, NC (incidently once when I was there, they had Faberge Eggs on display).
I’ll be seeing the Grand Canyon next month.
When I visited the Library of Congress in 1962, I was able to examine an original 1768 edition of Horace Walpole’s Historic Doubts on the Life and Reign of King Richard III. By “examine,” I mean that I took the book to a cubicle and turned the pages for several hours. It still amazes me that they allowed a teenage girl to handle such an old and frail volume. I almost said “fondle” rather than “handle.” This was one of the high points of my young life. Yep, I’m a book geek all right.
[ul][li]Napoleon’s underpants. 
(No, really. I was a docent for Napoleon: An Intimate Portrait during one semester of college, and the objects that were part of that exhibit were amazing to see up close. Napoleon’s underpants were probably the least interesting pieces, but the clothing items that were in the exhibit gave me a new appreciation for craftsmanship in textile work.)[/li][li]Samurai armor from the 16th and 17th centuries. (I got to touch these pieces and see them up close. They’re amazingly scary in the dark, even without people in them.)[/li][li]Þingvellir, Iceland. The seat of important events in the history of my ancestors, and still as majestic today as it was several hundred years ago.[/li][*]The European paintings in the Norton Museum of Art. Seeing photos does not do any of their pieces justice. When standing in front of some of their more massive and beautiful paintings, one feels so small in comparison.[/ul]
The Rosetta Stone. Especially since its impingement on my consciousness was so…unexpected. I was just placidly turning a corner in the British Museum and surprise, there it is. No ropes around it or anything.
The Last Supper. It’s nice. Go. Reserve in advance. Way in advance.
Rosetta Stone for me also, plus the Magna Carta.
Across the channel, the Mona Lisa and the Eiffel Tower
Since people mentioned the WTC, we visited the floor of the commodities exchange once, thanks to my f-i-l who used to be a commodities broker. We were through there all the time getting the PATH on our way from auditions.
But best - the liftoff of Apollo 17.
The Dome of the Rock
The Western (Wailing) Wall
Church of the Nativity in Bethlehem
Garden of Gethsemane
Via Dolorosa
Church of the Holy Sepulchre
Mary’s reputed home in Ephesus
Ephesus
Christopher Columbus’ birthplace in Genoa
Baalbek ruins in Lebanon
Byblos
Rome
The Acropolis
Saint Mark’s Cathedral in Venice
Hagia Sophia
Topkapi
Trophy of the Alps
Il Duomo in Milan
Notre Dame Cathedral
Eiffel Tower
Versailles
The Matterhorn
Dachau Holocasut Museum
The Pieta
The Mona Lisa
The Winged Victory of Samothrace
The Garden of Earthly Delights by Heironymous Bosch
oops, posted early
I went to the Elgar museum in Malvern with my grandparents.
Elgar, he of the Enigma Variations, was into puzzles and games. He owned a puzzle ring. I mentioned to the museum guard that I knew how to do them, so he unlocked the case and handed me Edward Elgar’s solid gold puzzle ring.
(Incidentally, I fucked it up and couldn’t solve it as it was different to all the other ones I’d seen. They had to put it back into the case all messed up. How embarrassing.)