Being tracked online is the price we pay for getting to wander the Internet free of charge.

FORBES: How much does Google know about you? There's an app for that.

The antihydrogen was then free to wander towards the walls, and thus annihilation.

ECONOMIST: Antihydrogen atoms are captured for the first time

Otherwise you are free to wander between broken-down walls and vanished gardens, look down on village roofs and muse on what it must have been like in its earlier incarnations.

BBC: Where the Marquis de Sade and Pierre Cardin meet

Unlike a store, a marketplace allows for what economists call price discovery: If buyers think the pomegranates are too expensive at one stall, they are free to wander over to another and try to get a better deal.

FORBES: Why the world would be better off with one big stock market.

Free to the public, anyone can wander around the workshops filled with artists hammering and carving their latest creations -- though if you want to clamber on one of the marvelous animals, you'll need to buy a ticket.

CNN: Giant mechanical animals stalk French theme park

Normally, an incoming electron would have a good chance of displacing one of these low-energy incumbents, but unlike the free electrons in metals, which are usually singletons, those in a superconductor tend to wander around in pairs.

ECONOMIST: Microrefrigeration