The Duke and Duchess of Cambridge — better known as Prince William and Kate Middleton — started their honeymoon in the Seychelles this week. Details about the trip are being kept quiet for security purposes, and to respect the newlyweds' privacy. But it's a safe bet that their 10-day getaway will be relaxing... and pricey. Here, a brief guide to what travel experts have to say about the royal honeymoon:

Where exactly did Will and Kate go?
The couple reportedly flew by private jet to Mahe Island airport, the gateway to the string of 115 islands about 1,000 miles off the eastern coast of Kenya. The Seychelles ministry of tourism would not reveal where in the Indian Ocean archipelago the royal couple headed next. The owner of North Island, an exclusive resort on the four-mile-long island of Desroches, told a German newspaper that Will and Kate are honeymooning at his place. But Britain's Guardian says others suspect the royal couple really went to Fregate Island Private, an eco-friendly luxury resort with just 16 villas — just a 20-minute helicopter flight from the main island's airport.

Sounds expensive.
It is. Just getting to the Seychelles from the U.K. by private jet could cost $100,000 roundtrip, says Lauren Streib at The Daily Beast. The chartered helicopter adds another $2,400 each way. And Fregate Island Private — which can accommodate a maximum of 40 people — charges $3,880 to $5,700 a night for its one- and two-bedroom villas (with private butler service), and $14,400 per night for the presidential villa. North Island would be no cheaper. Renting all 11 of its villas to ensure privacy would run $70,000 a day. And then there's the cost of security.

How much will security add to the tab?
Easily hundreds of thousands of dollars over the entire 10-day honeymoon, says Streib. William is second in line to the throne — after his dad, Prince Charles — so he's considered a top security risk, just like Queen Elizabeth herself. Getting his Scotland Yard detail to the hideaway could cost $100,000, plus another $400,000 for lodging, according to Streib. Add it all up and this could easily be a "$1 million honeymoon."

What will they get for the money?
The Fregate resort has a spa, a gym, a tennis court, paved hiking trails, and yoga classes. It also has a private marina offering sailing, windsurfing, motorboating, deep sea fishing, and scuba diving trips. The island is a mile in length and less than a mile wide. It has seven secluded beaches — one of which, Anse Victorin, was voted as the most beautiful beach in the world. The island is covered with lush tropical vegetation, says the Guardian, and is home to a colony of giant tortoises and rare wildlife, such as the magpie robin.

Why such a remote getaway?
Picking a secluded spot does more than discourage the paparazzi. Buckingham Palace has been on high alert since the killing of Osama bin Laden, and the Seychelles "can be virtually locked down" if need be, a royal family insider told E! online. "This island affords them not only the ultimate protection because of its remoteness and the ease with which it can be made secure," the source says, "but for the same reasons, it offers them the utmost privacy for a truly romantic honeymoon."

Sources: Wash. Post, Guardian, Daily Beast, Fregate Island Private, North Island, Express, E!