A £4.8bn incredible mega-project could completely transform a famous European city’s underground network and end their traffic woes for good.

Athens, home to two UNESCO World Heritage Sites, is renowned for its ancient ruins, museums and monuments.

However, the city can become incredibly congested with traffic especially on Sundays when many people return to the city after a weekend away.

But those in Athens will be pleased to hear that their traffic nightmares could soon be ended by the extension of Line 2 and the construction of Line 4 of the Athens Metro which could provide a much-needed solution to the city's traffic and air pollution problem.

The new Line 4 began its construction in October 2021 and Line 2, which ia entirely underground, began its extension to Ilion where tender started in 2023.

Transforming the city's underground network, Line 4 will be a whopping 23.7 miles, adding 35 new stations to the Athens Metro system.

It is scheduled to be completed in 2029 or 2030 with the cost of the entire project estimated to be £2.7 billion (€3.3 billion).

While the estimated cost for constructing the first phase of the new line is £1.2 billion (€1.51 billion).

Spanning 8 miles the first phase of Line 4 will be between Alsos Veikou and Goudi stations, adding 15 new stations.

Described as an "ambitious" project by project director Sissy Voutiritsa, work on Line 4 has proved to be a challenge because of sewage pipes, water supply networks, gas and telecommunications lines. The ancient city's underground archaeological monuments have also complicated efforts.

Part-funded by the European Investment Bank (EIB), the line is said to have generated 5,000 jobs and will lead to a reduction of 318 tons from Athens' daily CO2 emissions, according to the EIB.

The fourth line has been incorporated in the roadmap for the development and expansion of public transport in Athens since 2005.

Athens first metro was built by British entrepreneurs in 1869, connecting Thissio station to the port of Piraeus.

Until the turn of the 21st century Line 1 was the city's only underground line. So far this century Attiko Metro has opened two further line.