Giannella is the narrow northern sandy isthmus, or tombolo, that runs from the mainland to Argentario which forms, with the southern isthmus of Feniglia, the lagoon with Orbetello in the middle. There are numerous camping villages amongst the pine trees along the provincial road that runs the length of it, the tiny hamlet of Giannella itself with its beachside houses and a few bars and cafes, and a long stretch of sandy beach along its entire northern shore.

The WWF nature reserve entrance is on the main road north of Orbetello, and is a protected oasis, one of the most important lagoon ecosystems in Italy. The wetlands of the reserve are an important home for many migratory, wintering and nesting bird species, including flamingos, herons, eagles, terns, various species of ducks, and the almost extinct curlew. The flora includes pines, myrtle, juniper, and oak trees. The reserve forms an important companion to the protected forest reserve of Feniglia on the sourthern isthmus.