The first half of the Grand Line, colloquially referred to as Paradise, stretches from the Twin Cape to Mary Geoise and runs northwest to southeast. Its name, Paradise, comes from people that have returned from the New World; the second half of the Grand Line is a whole “new world” of adventures beyond anything that one might face in the first half, it is such an abhorrent challenge that the first half of the Grand Line is referred to as "Paradise" when comparing it to the second half.[4][5]
The first half of the Grand Line possesses highly volatile and unpredictable weather conditions, and the first leg of Paradise is especially chaotic; Reverse Mountain and the Twin Cape are a great starting point, from there a Log Pose can lock onto the magnetism of any of seven different islands, each of which is the first island in one of seven different routes that one can travel through to traverse the first half of the Grand Line, however the clashing magnetic waves and specific climates of those first seven islands result in extremely harsh weather patterns and ocean currents that change every few seconds.
Every island in Paradise presents its own unique challenges, and the level of difficulty seems to increase the farther one travels. Regardless of which of the seven routes one chooses, they are all an equal amount of trouble to travel through, and they all lead to the same place, the Sabaody Archipelago. Shakuyaku likened the first half of the Grand Line to a giant tournament of survival, with those who make it all the way to the Sabaody Archipelago as the cream of the crop. A countless number of pirate crews have entered the Grand Line, though only a small handful have made it that far.
In the anime soundtrack Believe by Folder 5, the chorus says "run towards paradise and believe in wonderland". The One Piece anime uses that soundtrack when the Straw Hat Pirate arrived in Logue Town, just before they entered the Grand Line.