Grammar JLPT Level N3 - Lesson 4

Structure of である:

Noun + である
［な］Adjective + である

Details about である:

である (or であります) is a construction in Japanese that is considered to be the formal equivalent of だ. This should not be confused with the polite speech word です, as である is simply a combination of the conjunctive form of だ, and the う - Verb, ある.
である may be used in any place that だ would usually be used, but is most likely to be found at the end of sentences/statements.

日本一(にほんいち)デカい博物館(はくぶつかん)はこの博物館(はくぶつかん)である。
The largest museum in Japan is this one.
ここから悲(かな)しいことが起(お)きるのである。
This is where something sad starts to happen. (Here comes the sad bit)
私達(わたしたち)が会(あ)えたのは運命(うんめい)であります。
It is destiny that we met.

である

Usage Notes for である:

であります (as opposed to である) is very formal, and will almost exclusively be used by people within jobs that absolutely require this level of formality (politics, police force, military, etc). Due to this, its use within regular conversation will sound stiff, or perhaps even like the speaker is jokingly being over polite.

名前(なまえ)はタナカであります！
My name is Tanaka! (Responding to a person in a higher rank in a military)
最後(さいご)のプリンを食(た)べたのは私(わたし)であります。
I am the one who ate the last pudding. (Jokingly polite)