When our thoughts turn to the cross of Christ what sort of mental picture do we have? Do we see the cross as something ennobling and glorious? Do we have warm sentimental feelings about crucifixion?

Crucifixion
In reality it was a stark and hideous spectacle. Crucifixion must surely be one of the most monstrous of all human inventions. Scourging sometimes preceded crucifixion. The condemned man was whipped with thongs of leather to which pieces of bone or metal had been attached There were times when people died as a result of scourging. Next the victim was nailed, through hands and feet to a wooden cross which was then lifted to a vertical position and fixed firmly in the ground. Then he was simply left to die. He was not killed -- just impaled in a position from which escape was impossible and left there until death overtook him

By sheer animal instinct the man would struggle to keep alive although life meant torture. Under its own weight his body would slump forward constricting the lungs and restricting breathing. But again and again, despite the intense pain in pierced hands and feet, he would heave his chest upwards to draw breath -- and keep alive. Ultimately death would come as a relief but only after hours and hours-often days-of indescribable agony. The Lord died after six hours on the cross, and Pilate was amazed that he had died so soon (Mark 15:44)

In the days when the Romans ruled, crucifixion was regarded with revulsion and disgust. The offender -- usually a dangerous political enemy or an incorrigible criminal -- was raised aloft and placarded before the people as a grim warning that disobedience does not pay. Those who witnessed the ghastly spectacle usually took the lesson.

Reference:

http://www.christadelphia.org/pamphlet/cross.htm