This much-loved gem in the Dodecanese island group of the southern Aegean Sea has all the best components at hand for a relaxing yet inspiring stay.
Chief among these on Kos are, naturally, fabulous weather, fine beaches, warm blue seas and tempting tavernas - all topped off with the many diversions of a peerless ancient history which Greece and her islands offer like no other.
Whether you're a first-timer or a repeat visitor to Kos, here is a guide to a selection of the very best places to visit and things to do on everybody's favourite little Greek island:
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Picture yourself at the Roman Odeon
Open your imagination to a glimpse of what live entertainment would have been like, Roman-style, courtesy of a trip to see the remains of the Odeon, the Roman theatre in Kos Town.
Traces of the original Odeon first started to reveal themselves in the 1920s, when archaeological excavations revealed evidence of these ancient ruins blinking once again into the light.
As you will see on your visit, Kos' Roman Odeon would have been quite a substantial venue at its height, with tiered rows estimated to house 750 people for their entertainment during live theatre and music events.
The Odeon is on the site of an earlier Greek theatre. Excavations have been kind to it: the front nine rows of the theatre are, you'll notice, fashioned in marble - presumably for the relative comfort of Roman bigwigs in attendance.
Granite seating further up into the gods was the more prosaic seating material given to Kos' lesser mortals.
The stage, orchestra pit and wings of the theatre add further context to the arena, while statues which were uncovered during the early 20th century digs can now be enjoyed in Kos Town's Archaeology Museum.
Don't forget to combine your visit to the Roman Odeon with a look around the adjacent Casa Romana, a once-distinguished house of 36 rooms, and almost certainly the domicile of the sort of Roman grandee who'd have no trouble reserving one of those golden-circle marble seats.
Might and majesty of Neratzia Castle
Some castles you'll have visited on your travels have been becalmed by the passage of time to take on a gentle, touristy quality; places for a mooch around stately rooms before being subtly funnelled into the souvenir shop.
Other castles simply stand there, brooding and fortified on high; shoulders back, arms folded, battlements ready and holding firm, with a clear, unspoken message to potential interlopers: "Don't mess."
Kos Town's 15th century Neratzia Castle (also known as the Castle of the Knights of St John), exerts an ever-powerful presence over the town and out to sea...and simply still screams 'fortress' beyond all doubt.
The views over the harbour from the castle ramparts provide impeccable photo opportunities, too.
Don't get stumped by the Tree of Hippocrates
A source of great pride in Kos' history is that Hippocrates, the oft-named father of modern medicine, is the island's most-famous son.
His importance is symbolised by the Tree of Hippocrates, which you'll find just outside Neratzia Castle.
It was under this oriental plane tree that Hippocrates was reputed to have taught students the rudiments of medicine.
The original tree on the site dated back no fewer than 2,400 years, although the present incumbent - believed to be a descendant of the older tree - is probably in the region of a still-impressive 500 years old.
Calm and charm in Kefalos
If you seriously want to kick back in a textbook, traditional Greek setting, then the town of Kefalos has all those time-honoured holiday requirements of calm and relaxation.
Kefalos is around 25 miles from Kos Town, at the far west point of the island.
The question of which and where are the best beaches on Kos (Therma, Marmari, Tigaki and Paradise beaches are notable favourites) is inevitably one of - literally - hot debate.
But for our money, the beaches in and around Kefalos are certainly worth seeking out, for indulging in the inestimable pleasures of sitting on the sands and going for a dip.
In the heart of old Kefalos, you'll happen upon that trademark, whitewashed charm characteristic of Greek villages, an interesting folk museum to visit (called, without ambiguity, the 'Traditional House'), plus laid-back cafes and a picture-perfect old square to complete the look.
Lots to see at Zia
While we're on that famously-horizontal Greek village vibe, as a pure island idyll on Kos it's hard to compete with the village of Zia, ten miles from Kos Town.
Zia is sightseer's delight noted for its amazing views and dazzling pink sunsets, while adding to the sense of mystery and beauty by being tucked away within forests wending their way up the side of Dikeos mountain.
The village is also home to three historic churches worthy of a look-in while you're there, plus a lovely old watermill. And make sure you buy a jar of the divine, locally-produced thyme honey when you're in the village.
Genuine nectar of the gods. What did we say about idyllic?
5 of the best Greek Islands
Fun and festivities in Mastichari
Nowhere is really very far from anywhere else on Kos. The resort of Mastichari, at 14 miles from Kos Town, is no exception to that rule.
Think resort, think beach again...and Mastichari has a perfect one of those, geared up for adrenaline thrills such as diving and windsurfing or, if it's more your thing, plain old swimming and sunbathing.
Mastichari village port is handy, too, for a spot of nearby island-hop day trips to Kalymnos and Pserimos.
Appetites whet on the beach, Mastichari is a terrific place for that unbeatable holiday pursuit which is, simply, a leisurely lunch of just-caught seafood in a taverna.
Time your visit for August, and you could be there to sample the fun, frolics, food, drink and music at the annual village shindig, the Mastachari Wine Festival.
With its perfect climate for viticulture, Kos is proud of its wine-making heritage. And in high summer, this village festival is the place to be to sample the joys of the local grape.
Fine wines at Triantafyllopoulous
Even if you as a wine lover don't find yourself on Kos for August's Mastichari Wine Festival, no matter. At other times throughout the wine-growing season, the island's lush plains have the much-lauded Triantafyllopoulous Winery to visit.
And that's certainly a name to grapple with after a couple of medicinal glugs of the estate's renowned Malagouzia Sauvignon Blanc!
Wines produced in the volcanic soil of these spectacular 50-hectare vineyards in Miniera are notable for both quality and rarity.
So savour them while you're on your Triantafyllopoulous wine tour, after which we'd recommend buying a few bottles, since you're unlikely to see them on supermarket shelves back home.
Healing and ancient history at The Asklepion
Named in reference and reverence to the Greek god of healing, Asclepius, this vast ancient temple complex turned sanatorium on the outskirts of Kos Town is the most significant - and most-visited - of the island's great sites from antiquity.
In crude terms, the Kos Asklepion was reputedly the world's first hospital - and the name itself was used across the ancient world as a generic term for centres of healing.
Kos' Asklepion is situated near natural springs and among pine forests on Dikeos mountain.
Hippocrates himself is central to Asklepion's story, as the sanctuary which combined healing and prayer was constructed in homage to the god of healing, after the death of the father of modern medicine.
Visitors to Asklepion these days can also witness an altar believed to have been built in the 4th century BC and dedicated to Asclepius, remains of temples to Apollo and Asclepius, plus the early Christian church of Panagia Tarsou.
What's cooking on Kos?
Think you know a bit about Greek food? It's perhaps easy - and inaccurate - to generalise, as each region, town, city and island have their own signature dishes and bespoke local fare, developed through the ages but with roots going way, way back.
So when in Kos, make sure you shake things up from the norm in the tavernas whenever you can by trying local specialities.
Among favourites peculiar to the island of Kos is posa cheese: a goat's cheese marinated in red wine, which is every bit as full-bodied as it sounds.
The town of Kefalos is particularly fond of kavourdisto with makarounes, a flavoursome dish of roast pork with pasta.
Back to the cheesy theme, make sure you indulge in a katimeria fried cheese pie, while we also recommend a regional variation of lasagne called pitaridia, which is every bit as enjoyable as its more famous Italian cousin.
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