Cancun is at the north end of the Riviera Maya, which also includes the island of Cozumel, so this is a huge area with over a thousand hotels to choose from. All that competition keeps prices down until the high season begins, so November is still a buyer's market. There are even ruins nearby and other cultural opportunities, so it's not all about sitting on the beach here. If you prefer a high-rise hotel overlooking a beach then stay in Cancun itself, but if you prefer to stay in a friendly town with many restaurant and shopping choices then head to Playa del Carmen, just a bit to the south, instead.
Also, as far as I hear, the worst that ever happens is they take your stuff. So if you leave your passport and most of your money in your hotel room, and keep your phone or camera hidden most of the time, there isn’t much to lose. I’m making it sound worse than it is really. I wouldn’t hesitate to go to Rio again, but of course I’d be aware of those few situations to avoid.
Pretty much everywhere is going to be at or near capacity for those dates because half the world is on Christmas break. Between Australia and New Zealand, I think New Zealand would be far more interesting for 10 to 14 days. In Australia you pretty much have to spend a few days in Sydney, a few days in Melbourne, and a few days at the Great Barrier Reef, all of which require flights and will be very crowded over those weeks.

There is no better time than December to discover a still (somewhat) under-the-radar part of the Caribbean. This verdant, five square mile island has seen a lot of activity recently, from a new mega yacht club to a Soho House to the Mandarin Oriental's first property in the Caribbean. More is on the horizon for this picturesque piece of paradise, but go before everyone else discovers it.
December is an ideal time to visit Mendoza in any year: The grapevines are alive, and the backdrop of the majestic Andes after the winter snows makes for dramatic scenery. Wine season is in full swing, and there’s a beer festival in Godoy Cruz during the first week in December—a four-day street party with live music and heavy partying. (Christmas and New Year’s, though, are high season for hotels, and the wineries close on December 24, 25, 31, and January 1.)
My two years in southeast Asia was over a few trips, although I did have my own apartment in Bangkok for 3 months and in Chiang Mai for another 3 months. As an American I didn’t have a national health restriction and I didn’t even have travel insurance. I don’t recommend it for everybody, but healthcare in those areas is extremely cheap and of pretty good quality. I went to a hospital once in Chiang Mai and I saw an English-speaking doctor for about US$7, and spent another US$25 or so on a prescription. My longest total trip was 3 years and 7 months (only a few years ago), and I went in and out of Southeast Asia a few times in that period.
Located off the coast of East Africa, the Seychelles—an archipelago consisting of 115 islands—is about as close to paradise as you can get. Crystal clear water, lush jungles, and powder-fine sand make it the ultimate early winter escape, particularly for romantic getaways. Book one of the 30 breathtaking pool villas at Six Senses Zil Pasyon, which is among the region's top luxury resorts. The hotel is situated on a private island that offers prime territory for snorkeling, sailing, kayaking, and hiking—plus, the spa has scenic pavilion-style treatment rooms that are worth the trip alone. Health conscious guests will be particularly impressed by the property's new "Eat with Six Senses" program, which is intended to make travelers leave vacation without the guilt that comes with overindulging. There are four tailor-made treatment plans that focus on sleep, detoxing, fitness, and more, depending on the issues you prefer to address.
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