From AH-64 Apache to Eurocopter Tiger, here's a look at the top five most advanced attack helicopters in service. This list also includes Mil Mi-28 Havoc, TAI T129 ATAK and Bell AH-1Z Viper.

The AH-64 Apache is the main attack helicopter of the US Army and the most widely used among Western countries and their allies. It is one of the most tested combat helicopters in history and has taken part in almost every major US and NATO operation since it was introduced in the army.
Across all models (A to E), the Apache has flown over five million hours, including 1.3 million in battle, according to reports.

The Russian Mi-28 Havoc was built to rival the USA's Apache. Strong body, heavily armed and designed for direct combat, this helicopter was first developed in the 1980s but entered the services in 2009.
It carries 16 anti-tank guided missiles that can take heavy armor, along with rockets and bombs. It is also armed with a 30mm Shipunov cannon and also has a titanium-protected cockpit.

The AH-1Z Viper is the modern version of the legendary AH-1 Cobra, and it has been updated with new technology for modern warfare.
The biggest change is its four-blade composite rotor, which makes the Viper faster, more stable and smoother to fly than older Cobras with two blades. It can carry up to 5,700 lbs of weapons on its six hardpoints. Its loadout can include up to 76 unguided Hydra rockets or 38 APKWS guided rockets.

Built by France and Germany, the Eurocopter Tiger is Europe’s most modern attack helicopter. Different countries use different models: Tiger HAP (France), Tiger UHT (Germany), Tiger ARH (Australia) and Tiger HAD (France/Spain).
The Tiger was among the first helicopters to include stealth features, such as radar-absorbing materials and low infrared visibility.

The Turkish T129 ATAK is an improved version of the Italian A129 Mangusta and was developed by AgustaWestland. Turkish Aerospace Industries redesigned it with stronger engines, upgraded electronics, better weapons and improved durability.
It was specially built to handle hot weather and high-altitude conditions. The T129 is mainly used by Turkey, though the Philippines and Nigeria have also bought it recently.