How to retrieve older versions of deleted objects?

The browse pages on openstreetmap.org don't allow you to see individual versions of objects like the API does. You can view the entire history of an object by appending /history to its URI, like this: https://www.openstreetmap.org/browse/way/211750802/history.

If you accidentally delete data like this, you have a number of options available:

• If you haven't closed your editor (JOSM in your case) you may be able to use its Undo function to restore the deleted data, then re-upload
• If you realise you've accidentally deleted data after closing JOSM, you can use the Reverter plug-in to restore it
• If you're not comfortable doing this, or can't get it working, ask on the Talk mailing list or the IRC channel where an experienced mapper may be able to help you revert your mistakes.