What can one say about Amitabh Bachchan that's not been said, written, sung, aired or paid tribute to in one form or another?

The answer to the frustration of most Big B's aficionados is, well, nothing. He's been successful for such a long time that words have exhausted, ink has dried up and thoughts sound like echoes of previously articulated sentiments. 

But that doesn't make him any less precious to those throngs of fans who assemble every single week to catch a glimpse of the star who represents dreams, hope, charisma and power.

It doesn't stop every aspiring and established filmmaker from approaching him for his/her 'dream come true' moment. It doesn't stop gushing fans in the garb of contestants and followers from wanting a hint of his acknowledgement.

It doesn't stop perfectly subdued journalists from turning into jelly-kneed teenagers on learning he's mentioned, followed or acknowledged them in print or social network.

His stardom, enthusiasm and aura is beyond any writer's hypothesis. It doesn't ask for analysis. It's simply out there, for us to contribute and him to appreciate.

This marvellous symbol of all things mega turns 70 on October 11.

And here's the deal. From 1969 to 2012, Bachchan has worked in over a staggering 180 movies as a poet, smuggler, farmer, physician, magician, superhero; you name it with a wide range of production houses, filmmakers, co-actors and technicians.

But it's not the statistic that opens one's mouth in awe and admiration. What makes this accomplishment unique is that nearly three fourth of his filmography is eminently watchable.

As part of his birthday special, we look at 70 of his best films in the past four decades beginning with Part 1 of the series.

Saat Hindustani (1969)

Though one of the more low profile releases of his career, Khwaja Ahmad Abbas's war drama earned Big B his first National award for Best Newcomer.

AB and wife Jaya starred together for the first time in BR Ishara's romance drama about a businessman's poetic son falling for a courtesan.

As the mute brother of Sunil Dutt in the desert love story Reshma Aur Shera co-starring Waheeda Rehman, Bachchan was both effective and restrained.

Before hitting the angry young man phase, AB played an unusual variety of characters.

Saudagar, where he dumps his resourceful wife to marry a pretty face, is one of them.

Though the role of Inspector Vijay Khanna in Prakash Mehra's revenge drama was turned down by many established heroes, AB's raging intensity proved just the right fit for the character changing his life and career for good.

How male ego can interfere with the marriage of the disproportionately talented playback singers is demonstrated with rare sensitivity in Hrishikesh Mukerjee's melliflous classic.

While his films with Manmohan Desai and Prakash Mehra were sure-shot money spinners, Bachchan made maximum number of films with Hrishida.

The actor collaborates with the Anand team to deliver yet another hard-hitting performance in this tale of class divide and friendship.

In the Manoj Kumar helmed multi-starrer, alongside Shashi Kapoor, Zeenat Aman, Moushumi Chatterjee, about socio-economic struggle jumbled with heaps of masala, AB plays an army man who loses his arm in war.

It's the splendid chemistry between its main cast -- Bachchan, Hema Malini and Pran that makes Kasauti featuring the hit song, Hum bolenga toh bolenge ke bolta hai, worth a watch.

An adaptation of Alfred Hitchcock's The Man Who Knew Too Much by writer turned director Narendra Bedi keeps things taut and tense all through its 145 minutes running time.

In Mili, Bachchan's angry young man image shows its complex facet but it's the eventual thawing of his hardboiled character and warm camaraderie with the effervescent Mili, essayed by Jaya B that makes this a tender experience.

If there's a movie as celebrated as Big B himself, it's got to be Ramesh Sippy's ode to spaghetti westerns brimming with all-time hit fictional characters like Gabbar Singh, Thakur Baldev Singh, Jai, Veeru, Basanti and Co.

Not enough due is given to this hide-and-seek drama about exes crossing path in an unlikely set-up -- he's a thief taking refuge in the house of his former girlfriend, now a police officer's wife aided by the seasoned credibility of AB, Sharmila Tagore and Sanjeev Kumar.

Learn a lesson or two in Botany as Amitabh Bachchan's Dr Sukumar pretending to be Dr Parimal memorises multiple chapters on corolla to produce hilarious results in Hrishikesh Mukerjee's comedy of swapped identities.