You can get the drop down list by either right-clicking on the back/forward buttons, or holding down the left button until the list appears.

The above posting is correct. But there is also another place to look.

You will see the orange Firefox Button providing you did not turn the "Menu Bar" on. You can turn them on by right-clicking next to the tabs and selecting 'Menu Bar'. Then your options will be under the 'History' menu option. Otherwise, read on if you have the Firefox (orange button).

Click on the Firefox image. On that menu, look at the 'History->' menu and you can see the old data in there as well including 'Recently Closed Windows' formally 'Recently Closed Tabs'.

Thanks TonyE. I did not know the back/forward buttons had that feature!