Restore closed tabs with no back up (iOS)
If your device is running iOS 8, you can access a list of the last 5 tabs you closed. This can be accomplished by:


Open Safari
Press the Tabs button in the lower-right corner of Safari
Press and hold the + symbol for a new tab
Wait for "Recently Closed Tabs" window to pop up. Access from there.


If the tabs do not appear in that list, you will have to navigate through the history to retrieve them. Note that if you use private browsing, no recently closed tabs (nor history, for that matter) will appear.