HANOI, Vietnam (CNN) -- On the streets of Hanoi, most physical evidence of war has disappeared, letting fade many memories of the Vietnam War.

CNN: 'Hanoi Hilton' now holds only painful memories

Over time, the markets recover their losses, memories fade, spirits revive, and the action starts up again, until, eventually, it goes too far.

NEWYORKER: What Good Is Wall Street?

However, as memories fade and new reasons to be angry take their place, Bush's time in office might start to look comparatively benign.

CNN: Will history be kind to Bush?

Memories fade and become less accurate.

CNN: Indicting John Doe: When all you have is DNA

They can even interrupt the trial to remind the jury that, say, a witness who has been put under stress of having a gun put to his head in a dark hallway might not be capable of making the correct identification, or that memories fade rapidly a few hours after a crime has been committed.

FORBES: New Jersey's New Eyewitness Rules Mean More Work For Experts

It takes time for newspapers to turn yellow and for memories to fade.

CENTERFORSECURITYPOLICY: Center for Security Policy | Antidote to Outrageous Palestinian Revisionism and Agitprop

It took 12 years for memories to fade.

CNN: Goodbye again, Newt Gingrich

For some users, those memories may never fade away.

FORBES: Can Google Maps Erase Bad iOS 6 Memories?

The bad memories are beginning to fade and people are willing to venture out.

FORBES: Jolie-Pitt's New Wine Is Scarce, Twelve Best Ros��'s To Try Instead

This reversed its previous under-performance in local elections in the capital, as London's memories of loonie Labour fade.

ECONOMIST: Local elections

Many have made profound sacrifices to uphold the ideals we cherish, carrying wounds that may never fully heal and dark memories that will never fade.

WHITEHOUSE: The White House

But these jottings have a second purpose: They're diary entries of sorts, bringing into sharp focus travel memories that might otherwise fade under the weight of years.

WSJ: Jeffery Deaver on Bathrooms Around the World | Traveler's Tale

Brian Prather's scenic design and Chris Lee's lighting work harmoniously, especially when family photos lining a hallway light up, then fade away like Mother's disappearing memories.

WSJ: Review: 'Memory Show' is poignant musical on loss

But sometimes memories take much longer to fade.

BBC: Renaming: Sleight of brand?

But especially among younger elected officials, memories of Milk are beginning to fade.

NPR: James Franco, From 'Freaks' To 'Milk'

Yet, some collective memories don't ever seem to fade.

CNN: Tiger moms: Don't turn your kids into robots

This is important as, looking ahead, we expect macroeconomic developments to feed through to a marked rally in the gold price and, with plenty of room for the gold:silver ratio to contract, particularly if memories of uncomfortable investor losses in silver during 2011 continue to fade, it is easy to see decent scope for sizable gains in the silver price this year.

FORBES: INTERVIEW: Thomson Reuters GFMS: Silver Could Reclaim $30/Oz In 2013