For over 2,500 years, kings and commanders have confronted the challenge of the Bosphorus, building rudimentary bridges out of boats and floating jetties to increase the size of their empires. Mandrokles of Samos crossed on huge connecting floats in 512 B.C. Persian Emperor Xerxes built a temporary bridge, as did Heraclius I of Byzantium, who crossed a chain of pontoons on horseback. Now that several bridges connect the shores of Europe and Asia, staying on the water has become more fashionable than actually crossing it. The shores are dotted with yalis, or classic waterfront mansions, built as early as the 18th century: yellow, pink, and blue wooden palaces perched along the waterfront. The surrounding neighborhoods (best visited by land) retain much of their characteristic village feel, in stark contrast to the restored homes inhabited by the likes of ex-Prime Minister Tansu Çillar.
Cruising up the straits is a bit easier these days than when Jason and the Argonauts sailed through in search of the Golden Fleece. A number of local tour companies organize daylong or half-day boat cruises up the Bosphorus on private boats, often with a stop at the Rumeli Fortress and visits to Beylerbeyi Sarayi. Unless you've gotten a guarantee that the tour will not wind up on one of the public ferries, skip the tour and hop on one of the less-pristine (but serviceable) city ferries and go the route yourself.
A one-way ticket on the Istanbul Deniz Otobüsleri ferry (IDO; tel. 0212/444-4436 toll-free in Istanbul; www.ido.com.tr) costs 7YTL ($6.10/£2.70). The last stop at Sariyer is the most visited -- and therefore the most touristy, but the potential for a side trip to the Sadberk Hanim Museum (Büyükdere Cad. 27-29, Sariyer; tel. 0212/242-3813; Thurs-Tues 10am-5pm; admission 6YTL/$8.10/£4.30) continues to make this disembarkation point one of the most popular. The museum, located in an old Ottoman house overlooking a section of the Bosphorus that was an old dockyard, houses a limited but excellent collection of artifacts representative of the progression of civilizations in Anatolia. If you're already up here, then it's worth a look; otherwise, you'll get a more comprehensive presentation of the same themes at the Museum of Anatolian Civilizations in Ankara.
A lesser appreciated alternative is to get off at Anadolu Kavagi instead, hike up the hill to the "Crusader's Castle" -- named for a carved cross decoration dating to the crusader invasion but actually a Byzantine structure used as a Genoese Palace in the 14th century -- and enjoy outstanding views of the European side.
The trip by sea from Eminönü (departures at 10:35am, winter only, and 1:35pm; the ferry makes a stop in Besiktas approximately 15 min. later) to the last stop at Anadolu Kavagi takes 2 hours (allow 6 hr. for the full round-trip excursion), with only two return departures leaving at 3 and 5pm. This schedule pretty much restricts the amount of jumping on and off you can realistically do in 1 day. Alternatively, you can take an IDO commuter ferry from any of a number of wharfs around the city to the destination on the Bosphorus of your choice for 1.30YTL/$1.15/50p.
