This is a feature I just learned today. At the bottom right of the Safari window is a tabs list button (looks like one piece of paper on top of another). Tapping that button will zoom out to a list of open tabs with a new tab button (the "+" button) at the bottom. Long-pressing the new tab button will yield a scrolling list of recently closed tabs. Quite handy if you happen to accidentally close a tab and want to bring it back. I'm not sure when this feature was included in iOS but it works perfectly on my iPhone 6.