Panic Button is a free Chrome extension which closes your currently-opened tabs on demand, restoring them later with a click.
The add-on is intended to be a browsing boss key. If you don't want someone to see exactly what you're doing online, click the button, all your current tabs are closed, and a new one appears at your "new tab" page. Click the Panic Button again when it's safe and the tabs reappear.
Handy configuration options include the ability to launch Panic Button from a custom hotkey, set a specific page to appear when it's activated, hide the toolbar button when it's used, and even password-protect your stored tabs to reduce the chance of snoopers finding out what you were doing.
PanicButton is a capable boss key for Chrome which makes it much easier to hide your browsing activities. But keep in mind that if you're using the browser on someone else's PC or network, there are many other ways they can monitor what you're doing online.