You can feature menus from your site in a widget area by using the "Add Submenu" option. Select "Override Title" to add your own title if desired (otherwise, the title defaults to the chosen menu, and links to the parent item), then select the "Starting level" (1st level, 2nd level, etc.).
This widget can be especially helpful on Landing Pages, which will not have a local menu by default once sub-pages are added (unlike Content Pages). The Submenu Widget can be used in place of the local menu when Landing Pages are used if desired. The Submenu widget can also be placed in other regions besides the left sidebar (unlike Content Pages) when used on Landing Pages.
How to Use the Submenu Widget
"Fixed parent item" allows you to select one individual parent item (and any sub-items of that parent item). "Expand all children of this tree" will expand all sub-items of top-level menu items in the widget. "Maximum expanded depth" allows you to specify the number of levels of sub-items that will be expanded. The numbering starts from the overall top of the menu.
If a page is in a menu and contains the Submenu widget, and the page is later moved to a different place in the menu, then the widget will need to be updated in order to find the correct "parent" menu item. If you move a page in the menu, then hit "Edit" for the Submenu widget and then save in order to update the parent item accordingly.