The tuba, trumpet, baritone,  trombone, and the french horn are all part of the brass family. Brass instruments are the hardest instruments to play.

To learn more about brass instruments, check out these sites:

http://hyperphysics.phy-astr.gsu.edu/hbase/music/brass.html

http://www.houghtonmifflinbooks.com/features/davidmacaulay/instruments2_mac.shtml

http://datadragon.com/education/instruments/brass.shtml