It is the largest and southernmost island in the Mariana Islands archipelago. Guam is a territory of the United States of America. It is considered to occupy a militarily strategic location, south of the Commonwealth of the Northern Mariana Islands. Guam is one of many islands that make up Micronesia, which politically consists of Belau (Palau), the Federated States of Micronesia (FSM), Kiribati (anthropologically having affinities with Polynesia and Micronesia), the Marshall Islands, and several remote islands designated as the U.S.-administered islands of the Central Pacific. All of Micronesia has close political ties to the U.S.
Northern Region- The Northern Region of Guam is lightly populated and mostly owned by the U.S. Military. Cities like Dededo and Yigo are in this region. The Northern Region contains Ritidian Beach, one of the most isolated, beautiful beaches in Guam. The Northern Region is the least-visited by tourists.
Central/Metropolitan Region- The Central Region holds the majority of Guam's population and cities. A lot of shopping and restaurants are located in this area. This is the island's most visited area. This area contains most of Guam's cities and the island's international airport. It is prone to heavy traffic congestion. The Central Region is the most diverse. The population of the Central Region is approximately 120,000, and expected to grow to at least 140,000 by 2015.
Southern Region- Guam's Southern Region is mostly rural and picturesque. It is one of the most untouched and undeveloped areas on the island and the Chamorro culture is most preserved here. Cocos Island and the black sand beaches at Talofofo are popular places to visit in this region.
No true cities exist on Guam (if one uses the 50,000 person rule), but each "city" represents an individual township, all of which have mayors and limited autonomy within the central government. The largest population concentration is in the center of the island, since the south is fairly lightly populated and the north is mostly owned by the US military.
Most of the island's population is in the central metropolitan area (includes the cites of Tumon, Agana, Dededo, Barrigada, Tamuning and Agana Heights) (metro pop. ~120,000)
Guam was ceded to the U.S. by Spain in 1898 after the Spanish-American War. Captured by Japan and its army in 1941, it was retaken by the U.S. three years later. The military installations on the island are some of the more strategically important U.S. bases in the Western Pacific.
The economy depends on U.S. military spending, tourism, and the export of fish and handicrafts. Total U.S. grants, wage payments, and procurement outlays amounted to $1 billion in 1998. Over the past 20 years, the tourist industry has grown rapidly, creating a construction boom for new hotels and the expansion of older ones. More than 1 million tourists visit Guam each year. The industry has recently suffered setbacks because of the continuing Japanese slowdown; the Japanese normally make up almost 90% of the tourists. However, Guam tourism is branching out to attract people from other Asian countries such as South Korea and China. Most food and industrial goods are imported. The possibility of a large military buildup has generated a lot of interest in increasing the tourist facilities on the island.
Guam enjoys a tropical marine climate: generally warm and humid, moderated by northeast trade winds. The dry season runs from January to June, the rainy season from July to December, though with little seasonal temperature variation. During the rains, squalls are common, though destructive typhoons are rare.
The entry requirements for Guam are largely the same as those for the U.S, and nationals of all countries not needing a visa to enter the U.S. do not need a visa to enter Guam, although they may require an ESTA travel authorization. Foreign citizens may enter Guam using one of three options: (1)- the U.S. Visa Waiver Program, (2)- the Guam/CNMI Visa Waiver Program or (3)- a valid U.S. visa. If you are using the Guam/CNMI Visa Waiver Program, you do not need to apply for a travel authorization prior to going. The Guam/CNMI Visa Waiver Program includes seven U.S.-VWP countries (Australia, Brunei, Japan, New Zealand, South Korea, Singapore and the UK) plus Hong Kong, Malaysia, Nauru, Papua New Guinea, Taiwan and Russia(from 15.01.2012). Foreign citizens using the U.S.-VWP may stay 90 days, while citizens using the Guam/CNMI-VWP may stay for 45 days. Citizens of non-VWP countries must apply for a U.S. visa at any U.S. embassy.
Won Pat Guam International Airport (GUM) is the only civilian gateway to the island.
The airline servicing Guam is United Airlines, which offers non-stop service to Honolulu with onward connections in Honolulu to Chicago,Denver,Houston,Los Angeles,Newark,San Francisco,and Washington-Dulles. It also offers non-stop flights from Guam to Cairns in Australia, as well as most major cities in Japan, Palau, Manila and Cebu in the Philippines, and many of the Federated States of Micronesia.
All other service to Guam is through East Asia on Delta Air Lines, and JAL (both serving Tokyo, Osaka and Nagoya), Korean Air (Seoul and Osaka), ANA (Osaka), China Airlines (Taipei) and Philippine Airlines (Manila).
There is no regular ferry service from Guam, but cruise ships do stop in Guam on various itineraries, generally as part of a Pacific crossing or world circumnavigation.
Driving is fairly simple and similar to the mainland US. Roads are not graded to US standards and are very slippery in rain, take caution. The main route on the island is Marine Corps Drive/Guam Route 1 (Better known as Marine Drive). On main roads in Guam, expect congestion. Many people purchase vehicles described as "Guam Bombs" which are older vehicles that are great to get around in and affordable.
Buses are available, but the frequency at which they operate is low, you may end up waiting 1+ hours for a bus.
Walking is only possible in the central business districts of Hagåtña and Tumon. Walking anywhere else around the island is hazardous due to dangerous vehicular traffic and the lack of sidewalks.
English, Chamorro, Japanese are the official languages of Guam. English is a second language for most people, though Chamorro words are an integral part of the local vocabulary, and like any area, a local accent of English exists. Chamorro borrows many words from Spanish, and many place names are pronounced as in Spanish, with key differences: "y" is pronounced as a "j" and vice-versa, such that the local name Reyes is pronounced ray-jez.
There are many retail outlets in Guam, including DFS (Duty Free Shoppers) which operates several stores in hotels, a large "Galleria," and a store in the Guam Airport. Further, visitors to Guam will note some of the same shopping opportunities that exist in "the States." Although there is no Wal-Mart, there is a large K-Mart that does a very high volume of business. Indeed, visitors who are used to the voided cavernous K-Marts in the U.S. may be surprised to find that they can barely squeeze through the aisles of the Guam K-Mart.
The Tumon Bay area possesses many duty-free shopping outlets and boutiques catering to Japanese tourists. Among these are boutiques selling Bvlgari, Chanel, Cartier, Dior, Fendi, Ferragamo, Gucci, Hermes, Louis Vuitton, Rolex, and more.
For U.S. citizens, Guam offers greatly increased customs exemptions coupled with duty and tax free importation of goods. However, take care with the basic prices offered in stores. Much merchandise has been shipped a very great distance at no small cost.
Despite its small population Guam has a range of restaurants, including Ya Mon's Jamaican Grill (locally owned & soon-to-be franchised), Planet Hollywood, Hard Rock Cafe, Tony Romas and Chili's are in a building next the the Guam Premier Outlets. Major hotels and restaurants serve continental meals and ethnic dishes.
Fresh seafood is bountiful. Fresh fish, octopus, and crab are either grilled or baked with vegetables or fruit, sashimi, and in other ways unique to the Pacific.
Travelers who venture further will find Chamorro, Japanese, Korean, Thai, Vietnamese, Filipino, Chinese, Mexican, and European restaurants, each with its own distinct ambiance. Chamorro Village offers a great variety of choices for local chamorro food, especially Wednesday nights. Of course, American fast food chains, such as Wendy's, Burger King, McDonald's, Taco Bell, Long John Silvers, Pizza Hut, Winchells Donuts and Dominos are common.
Locals pride themselves in BBQ'ing and it is a frequent event in Guam. Families and friends often get together and for BBQs, so if you visit ask about BBQ's. It's a good chance you'll get invited!
The main tourist area is around Tumon Bay, which has a number of high-rise hotels and resorts similar to Waikiki Beach. Cheaper accommodations exist near the airport, especially around the village of Harmon. Be aware that Harmon hotels tend to be on the seedier side since Harmon is a mixed industrial/residential neighborhood. Many of the flights scheduled through Guam to other locations (especially in Asia) often require an overnight layover, so plan ahead. Some hotels offer airport pickup, as taxis can be quite expensive.
The University of Guam  provides higher education opportunities for students on Guam, as well as providing higher education for much of Micronesia. The UOG is in Mangilao, on the central eastern side of Guam. Students can earn various Undergraduate degrees and several programs offer degrees at the Masters level. Two of the better known Masters level programs include the (1) Environmental Science Program, focusing on Agricultural sciences through the College of Agriculture and Life Sciences (CALS) and Hydrology and Water Resources through the Water and Environmental Research Institute of the Western Pacific (WERI; ); and (2) the Marine Laboratory (http://www.uog.edu/marinelab), which focuses on Marine Biology and other environmental issues.
The largest employers are the government of Guam and United Airlines, followed by a large duty-free retail firm (DFS Guam), the U.S. Federal Government, the hotel industry and services sectors. Guam has two large military bases and several smaller military installations that employ many people. The only U.S. Air Force base is Andersen Air Force Base on the northern tip of the island. The U.S. Navy has a large naval station -- Naval Station Guam --located on the west-central part of the island near the village Agat.
Micronesian Diver's Association has information on the may local dive sites as well as boat dives around the island. Highlights include: The Blue Hole, a more advanced dive with an incredible drop through a hole in the reef; and the Kitzagawa Maru and Tokei Maru, two Japanese warships sunk out in Apra Habor.
Observe caution when engaged in water activities on Guam, as in any coastal area, as currents can be swift and unpredictable, depending on the season. During the rainy season (from about August until March), water can pool unevenly on road surfaces. Pooling of rain water can lead to flooding of roads in the southern half of Guam, which does not have sewer drainage built under the road surfaces. Furthermore, many roads are in disrepair and potholes are frequent, which can easily blow out tires. Violent crime is fairly low, but property crime tends to be high, so safeguard valuables in vehicles. Rental cars have stickers and can be targeted by thieves. Guam is in a major earthquake zone, and these occur every few years. That said, there have been few casualties to date.
The civilian Guam Memorial Hospital is in Tamuning, in the Central Region. If you have access to military bases, there's a Naval Hospital.
The Chamorro people, also known as the Chamoro or Chamoru, are indigenous to Guam. They possess a culture that mixes Asian, Spanish, and American cultures, and in general the people are gregarious and welcoming to visitors. Observe common courtesies and tend to err on the modest side, especially with clothing. Other cultures found in Guam include those from the Philippines, Japan, China, Korea, and other countries.
The Chamorro population is predominantly but not exclusively Catholic, with Protestantism also popular. On Guam, rosaries take the place of large formal gatherings to remember those whom have passed away, and such congregations can occur for up to 20 years after someone has passed.