The tract of land the United States received at the end of the Mexican-American War in 1848 was called the Mexican Cession.
the Republic of Texas.
the Gadsden Purchase.
the Louisiana Purchase.

after the roman empire fell, some of its cultural achievements lasted for some time and others were lost. lost achievements include architecture , coins, and literacy. however, several things remained, such as the language. people may not have spoken this language in every city, but it influenced the languages they did speak. they also created the julian , which was commonly used until the eighteenth century.

in february 1787, congress decided that a convention should be convened to revise the articles of confederation, the nation’s first constitution. in may, 55 delegates came to philadelphia, and the constitutional convention began. debates erupted over representation in congress, over slavery, and over the new executive branch. the debates continued through four hot and muggy months. but eventually the delegates reached compromises, and on september 17, they produced the u.s. constitution, replacing the articles with the governing document that has functioned effectively for more than 200 years.

1960: wilma rudolph was the first woman to win three olympic gold medals in track and field at one olympic games. she was an american sprinter from tennessee, she was acclaimed the fastest woman in the world. she was among the most visible black women in america and abroad. she became a role model for black and female athletes. she was also known as a civil rights and women right's pioneer.

1973: billy jean king is an american former number one tennis player. she represented the united states in the federal cup and the wightman cup. for three years she was the usa's captain in the federation cup. she defends gender equality and has been a pioneer for equal and social justice. at the age of 29, she won "the battle of sexes" tennis match against the 55 year old bobby riggs. she was also the founder of women's tennis association and the women's sports foundation.  

1983: tamara mckinney becomes the first american female skier to win the alpine world cup overall championship top. she was the only american to hold that title for a quarter century until 2008.

1992: manon rhéaume, from canada,   becomes the only woman to start in a national hockey league game in an exhibition game for the tampa bay lightning . she played on the canada women's national ice hockey team winning gold medals in 1992 and 1994. and silver medals in 1998. manon marked the first time a woman appeared in a regular season professional game with her first appearance against the salt lake golden eagles.

2013: serena williams won 78 of 82 matches at the age of 31. she is an american professional tennis player. she reached the number 1 ranking for the first time on july, 8, 2002. at the age of 16, she played against karsten braasch the battle of sexes. she was the highest paid female athlete in 2016. she is a unicef ambassador .

on april 6, 1917, the u.s. joined its allies--britain, france, and russia--to fight in world war i. under the command of major general john j. pershing, more than 2 million u.s. soldiers fought on battlefields in france.