Symi is a small island not far from Rhodes, more known for its colourful neoclassical houses near the port and the 18th century monastery of Archangel Michael Panormitis.
Personally I think the island has been overrated and overpriced. For a day trip would easily costed €30-€50 for a return trip. Almost everything is more pricey than Rhodes as they rely on boat to transfer most of the goods from Rhodes.
For a change of view, there is no harm to visit the island as it still has nice beaches to offer.
Walk around the port
Walk around the island or take a train ride
Spotted a German bunker on my way to Nimborio beach from the harbour.
View along the coastal road