A large part of the route takes place on the Mures Promenade and surrounding the Arad Fortress.
The Arad Fortress is one of the most important historical monuments existing at present in the west area of the country and it was built in the second half of the seventeenth century, being considered one of the most impressive military fortification of those times. Arad fortress was built in a Vauban -Tenaille style after the Austrian architect Philip Ferdinand Harsch’s plans at the request of Maria Theresa Empress having the shape of a star with six corners. The work lasted 20 years, with minor interruptions caused mainly by lack of manpower, so the fortress was completed in 1783.
After finishing working, various military units were placed in the fortress and thus Arad became a military-political centre of the Austrian domination in the area. History of the city in its more than 200 years of existence, is linked to important events. During Horea's Revolution in 1784, the city was one of the action centres of the imperial troops against the rebels. During the Napoleonic wars, many French prisoners were kept in the fortress. After the revolution from 1848, in the city pillboxes were imprisoned and condemned many revolutionaries including EftimiÔe Murgu. With the end of the nineteenth century, when the strategic concept had changed, the city lost its importance and became a simple barracks.
About Arad fortress you can find more here

The municipality of Arad, the baroque citadel as it is known the town from the Mures river, has a series of alternatives to visit given by the multitude of tourist attractions concentrated in the Arad urban assembly, located at south of the Mures river loop (which surrounds the fortress of Arad ) and developed around the main artery of the old town - Revolution Avenue. It is composed of a series of settlements, historical monuments dating back from 18th – 19th centuries.
So, for those who want to "return to history" with at least a century, we suggest them to visit:

The Administrative Palace (City Hall of Arad), located at no.75, Revolution Avenue, built between 1874-1876. It is worth visiting: the palace tower having a 54 m height, with its clock brought from Switzerland in 1878 that still works today, and of course the stained glasses, made by the artist Sever Frenţiu which symbolize the four seasons.

• The Szantay Palace, located at no.3 on Horia Street, dating from 1911 and having a secession predominant architectural style; today the building is used for dwellings and commercial spaces.

• The National Bank Palace, located at no.72 on Revolution Avenue and built during the Revolution from 1905 to 1906, is still the county headquarters of the National Bank of Romania.

• The Cenad Palace, located at no.73 on Revolution Avenue being built in the end of 19th century; it was the headquarters of the Arad – Cenad Railway Company; today the building is designed for human habitation.

• The Evangelical Lutheran Church, also known as the Red Church because of its construction material (brick); it is located at no.61 on Revolution Avenue dating from 1906.

• The Arad Cultural Palace (today the State Philharmonic and County Museum Complex) located at no.1 on G. Enescu Street, built in the 1911-1913 period; the predominant architectural style of the building is secession.

• The Justice Palace, located at no.2 on General V. Milea Street dated from 1892.

• “ Ioan Slavici” State Theatre, located at no.103 on Revolution Avenue and dated from 1874; it is the institution that maybe evokes the best the strength of cultural activities as art show, together with The Old Theatre, located at no.3 on Gheorghe Lazar Street and dated from 1817; the predominant architectural style of these two buildings is the baroque.

• The “Iacob Hirschl” House, located at no.1 on Gheorghe Lazar Street, built in 1817 in a predominantly baroque architectural style.

More touristical attractions you can find here