The National Academy of Sciences (NAS) is a United States nonprofit, non-governmental organization. NAS is part of the National Academies of Sciences, Engineering, and Medicine, along with the National Academy of Engineering (NAE) and the National Academy of Medicine (NAM).

As a national academy, new members of the organization are elected annually by current members, based on their distinguished and continuing achievements in original research. Election to the National Academy is one of the highest honors in the scientific field. Members of the National Academy of Sciences serve pro bono as "advisers to the nation" on science, engineering, and medicine. The group holds a congressional charter under Title 36 of the United States Code.

Founded in 1863 as a result of an Act of Congress that was approved by Abraham Lincoln, the NAS is charged with "providing independent, objective advice to the nation on matters related to science and technology. … to provide scientific advice to the government 'whenever called upon' by any government department."[2]

The Academy receives no compensation from the government for its services.[3]

The Academy currently has 2,984 members and international members. Existing members elect new members for life. Up to 120 members are elected every year; up to 30 foreign citizens may be elected as international members annually. The election process begins with a formal nomination, followed by a vetting period, and culminates in a final ballot at the Academy's annual meeting in April each year. Members are affiliated with a section -- a specific scientific field -- in one of six so-called "classes": (1) Physical and Mathematical Sciences; (2) Biological Sciences; (3) Engineering and Applied Sciences; (4) Biomedical Sciences; (5) Behavioral and Social Sciences; and (6) Applied Biological, Agricultural, and Environmental Sciences.[6] Since its founding, the Academy has elected 6,457 members. Harvard University is associated with the most members (329), some 5% of the all-time total. The top ten institutions, half of which are Ivy League universities, account for nearly 28% of all members ever elected.[11]

Mediterranean home styles are made of stucco, so they’re most common in warm climate states like Arizona and California. These homes grew in popularity in the 1920s and ‘30s after being featured as homes for the rich and famous on the silver screen.

Mediterranean-style homes include Spanish and Italian architectural elements. These key features make them easy to spot:

• Stucco walls painted white or brown
• Classic red tile roofs
• Arched doorways and windows
• Ornamentation including wrought iron, heavy doors, and decorative tiles

Mediterranean homes still carry the feelings of class and luxury they were built with over 100 years ago, with an added element of history and charm.

Shingle-style homes took influence from Colonial architecture rather than Medieval Europe. Ornamentation became simpler towards the end of the Victorian-era and Shingle-style homes are best known for their creative floor plans and signature shingles on exterior walls.

Shingle Victorian homes are identified by these interior and exterior features:

• Shingles cover the entire exterior
• Asymmetrical interior layouts without a central hallway
• Emphasis on horizontal planes
• Custom built to meld with the nature surrounding the house

Shingle-style houses were designed as a work of art and encouraged creativity in their use of shapes and features.

House styles will continue to evolve with influences from history, culture, and our lifestyles. All of these house styles can be seen and celebrated across the US and have their own stories to tell. Choose the house style that fits your lifestyle, location, and, of course, personal style best. Then check your credit score, get pre-approved, and start house-hunting.

The Pueblo Revival was inspired by the indigenous Pueblo people’s architecture in the Southwestern US. Pueblo homes were made of adobe or stucco and designed to handle the extreme temperatures of the desert.

Architects in California began to explore the Pueblo style in the late 19th century and the Pueblo Revival style spread across New Mexico, Arizona, and Colorado.

The Pueblo Revival hit its peak in the 1930s in Santa Fe, and these Pueblo-style elements are still popular in the Southwest:

• Rounded corners and irregular shapes
• Earth tones that reflect the desert colors
• Stepped effects with higher floors becoming smaller
• Flat roofs with parapet trim
• Exposed roof beams extending past the walls

The Pueblo Revival style is also commonly called Adobe or Santa Fe style architecture.

Second Empire homes were a modern Victorian-era style that started in France before spreading through the Northeastern and Midwestern United States. Second Empire architecture features similar ornate Victorian trends, though generally offers a simplified Victorian aesthetic.

These elements help identify a Second Empire home:

• Uniquely shaped Mansard Roof
• Decorative window framing and dormers
• Decorative rails or balustrades around terraces and staircases
• Iron roof crest and eaves with support brackets

Second Empire homes are also easy to identify since they’re the only Victorian-era style that often features a symmetrical, rectangular floor plan.

The United States has 63 national parks, which are Congressionally-designated protected areas operated by the National Park Service, an agency of the Department of the Interior.[1] National parks are designated for their natural beauty, unique geological features, diverse ecosystems, and recreational opportunities. While legislatively all units of the National Park System are considered equal with the same mission, national parks are generally larger and more of a destination, and hunting and extractive activities are prohibited.[2] National monuments, on the other hand, are also frequently protected for their historical or archaeological significance. Eight national parks (including six in Alaska) are paired with a national preserve, areas with different levels of protection that are administered together but considered separate units and whose areas are not included in the figures below. The 423 units of the National Park System can be broadly referred to as national parks, but most have other formal designations.[3]

A bill creating the first national park, Yellowstone, was signed into law by President Ulysses S. Grant in 1872, followed by Mackinac National Park in 1875 (decommissioned in 1895), and then Rock Creek Park (later merged into National Capital Parks), Sequoia and Yosemite in 1890. The Organic Act of 1916 created the National Park Service "to conserve the scenery and the natural and historic objects and wildlife therein, and to provide for the enjoyment of the same in such manner and by such means as will leave them unimpaired for the enjoyment of future generations."[4] Many current national parks had been previously protected as national monuments by the president under the Antiquities Act or as other designations created by Congress before being redesignated by Congress; the newest national park is New River Gorge, previously a National River, and the most recent entirely new park is National Park of American Samoa. A few former national parks are no longer designated as such, or have been disbanded. Fourteen national parks are designated UNESCO World Heritage Sites (WHS),[5] and 21 national parks are named UNESCO Biosphere Reserves (BR),[6] with eight national parks in both programs.

Thirty states have national parks, as do the territories of American Samoa and the U.S. Virgin Islands. The state with the most national parks is California with nine, followed by Alaska with eight, Utah with five, and Colorado with four. The largest national park is Wrangell–St. Elias in Alaska: at over 8 million acres (32,375 km2), it is larger than each of the nine smallest states. The next three largest parks are also in Alaska. The smallest park is Gateway Arch National Park, Missouri, at 192.83 acres (0.7804 km2). The total area protected by national parks is approximately 52.2 million acres (211,000 km2), for an average of 829 thousand acres (3,350 km2) but a median of only 208 thousand acres (840 km2).[7]

The national parks set a visitation record in 2017, with more than 84 million visitors and set a further record in 2018 with a 0.1% increase.[8][9] Great Smoky Mountains National Park in North Carolina and Tennessee has been the most-visited park since 1944,[10] and had over 14 million visitors in 2021.[11] In contrast, only about 7,000 people visited the remote Gates of the Arctic National Park and Preserve in Alaska in 2021.

American popular music has had a profound effect on music across the world. The country has seen the rise of popular styles that have had a significant influence on global culture, including ragtime, blues, jazz, swing, rock, bluegrass, country, R&B, doo wop, gospel, soul, funk, punk, disco, house, techno, salsa, grunge and hip hop. In addition, the American music industry is quite diverse, supporting a number of regional styles such as zydeco, klezmer and slack-key.

Distinctive styles of American popular music emerged early in the 19th century, and in the 20th century the American music industry developed a series of new forms of music, using elements of blues and other genres of American folk music. These popular styles included country, R&B, jazz and rock. The 1960s and 1970s saw a number of important changes in American popular music, including the development of a number of new styles, such as heavy metal, punk, soul, and hip hop. Though these styles were not in the sense of mainstream, they were commercially recorded and are thus examples of popular music as opposed to folk or classical music.

Around the 1820s, Americans experienced a renewed interest in classic Greek and Roman culture. This cultural shift was a natural fit for architects, who brought the Greek Revival house style to life.

Greek Revival architecture became popular in homes as well as businesses, banks, and churches. Prominent features include:

• Easy to identify shapes, including a rectangular building and triangular roofs
• Gable-front designs
• Large porches and protected entryways
• Greek-inspired columns both square and round

Greek Revival homes often have decorative trim and moulding around the front door and windows. These ornate features and columns are easy ways to identify Greek Revival architecture.

Gothic Revival architecture grew in the mid-19th century and was one of the early styles of Victorian-era homes. The Gothic Revival style takes influence from Medieval Europe and was designed as a country home. Architects believed the asymmetrical design and ornamentation complemented the nature of rural America.

Gothic Revival homes can be identified by their:

• Pointed arch in windows, doors, and decoration
• Elaborate wood trim vergeboards and bargeboards
• Steeply pitched roofs and front-facing gables
• Towers and turrets resembling medieval castles

Gothic Revival architecture was a popular style for schools and churches as well as rural homes.

Cape Cod homes are similar to the British or American Colonial homes, though they originated further north in Cape Cod, Massachusetts. These are often seen as the classic American family home since the style’s revival in the 20th Century.

Cape Cod homes are identified by their:

• Shingle exteriors
• Modest size and ornamentation compared to British Colonial homes
• Originally single-story homes
• Large central fireplaces
• Attic lofts (20th-century revival)
• Dormer windows (20th-century revival)

Cape Cod homes are built of local wood and stone to withstand the north-eastern weather. This exterior weathering provides an iconic weathered-blue color to these homes.