Google-maps – Embedding in New Google Maps

According to The New Google Maps, Now Available (May 17, 2013)

"My Places" is not part of the new Google Maps interface. Click the "options" icon in the black navigation bar, select "My Places" and you'll go back to the old interface. It's a trick that lets you temporarily switch to the old interface. You can also click "classic maps".

However you can still access your "My Places" by going directly to Google Maps - My Places which will contain all of your old maps (which are still editable).

You can also use Google Maps Engine Lite to create and view custom Google Maps.

I was able to import a "my places" map to mapsengine as of late August (maybe they didn't have the feature before).

1. Make a new map.
2. click "import" under untitled layer
3. select "my maps"
4. all your "my places" maps will be listed and you select the map you want to import