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]

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.

Cottage-style homes are often quaint and cozy — emphasizing charm and comfort over ornamentation. Cottage houses come in a variety of styles and can mimic bungalows, Tudor house styles, and more.

Look for these designs to identify a cottage:

• Asymmetrical exterior
• Typically one to one-and-a-half stories
• Traditional aesthetics that aren’t too rustic
• Open floor plans with wide halls and doorways

A cottage house style is extremely versatile, and its small size makes it great for small families or guest houses.

Queen Anne homes were popularized in the later Victorian era, beginning around 1880. This style is the quintessential Victorian home for many, with ornate woodworking and decor inside and out.

Queen Anne homes have key regional differences across the country, but maintain these essentials:

• Textured walls with decorative shingles or half-timbering
• Large round or polygonal tower at the home’s corner
• Steeply pitched and asymmetrical roof
• Decorative spindles on porches and trim
• Decorative single-pane or stained glass windows

Queen Anne architecture is most common in homes, but can also be seen in schools, churches, and office buildings.

The Royal Exchange in London was founded in the 16th century by the merchant Sir Thomas Gresham on the suggestion of his factor Richard Clough to act as a centre of commerce for the City of London.[1] The site was provided by the City of London Corporation and the Worshipful Company of Mercers, who still jointly own the freehold. It is trapezoidal in shape and is flanked by Cornhill and Threadneedle Street, which converge at Bank junction in the heart of the city. It lies in the ward of Cornhill.

It has twice been destroyed by fire and subsequently rebuilt. The present building was designed by Sir William Tite in the 1840s. The site was notably occupied by the Lloyd's insurance market for nearly 150 years. Today the Royal Exchange contains Fortnum & Mason The Bar & Restaurant, luxury shops, and offices.

Traditionally, the steps of the Royal Exchange are the place where certain royal proclamations (such as the dissolution of parliament) are read out by either a herald or a crier. Following the death or abdication of a monarch and the confirmation of the next monarch's accession to the throne by the Accession Council, the Royal Exchange Building is one of the locations where a herald proclaims the new monarch's reign to the public.

Townhomes are common in cities and densely populated neighborhoods. Townhouses are tall and narrow homes designed to make the most out of vertical space without too much of a yard or garden area.

Homes are considered townhouses when they:

• Share one or two walls with adjacent homes
• Have their own entrances
• Are built with multiple floors to maximize vertical space
• Often share a similar style to their neighbors’ homes and may operate under an HOA

Townhouses can be built to mimic other architecture styles, like Italianate and Greek Revival, while maintaining the condensed, vertical floor plan.

The French Colonial house style can be seen around the world and has significant variety among its sub-styles.

French Colonial houses have the same symmetry as other Colonial homes with these distinct features:

• Dormer windows, including one centered above the door
• External stairs to enter higher floors
• Iron stairs and balconies
• Slightly raised basements to support the floor

French Colonial houses are most similar to Spanish Colonial houses and easily identified by their elaborate iron balconies, stairs, and entrances.

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.