The greatest artistic triumphs of the romans were in

 The Semicircular Arch and the Colosseum  are examples.

The Semicircular Arch is more popularly known as the Roman Arch. It is a strong arch usually found in aqueducts or bridges.

The Colosseum  is an oval ampitheatre also known as Flavian Ampitheatre. It can hold approximately 50 000 to 80 000 spectators

The purpose of having competing political parties is to represent different opinions.

Political parties are fundamental institutions of democracy. By competing in elections parties offer citizens the opportunity to fulfil their right of choice in governance, and while in opposition they can hold governments accountable.

When citizens join political parties, volunteer their time, give money and vote for their leaders, they are exercising their basic democratic rights.