Legendary's Godzilla may surpass $400 million this weekend the movie is currently at $180 million US as of 6/6 and $200 million internationally as of 6/1. 

The film still hasn't opened in two major markets China and Japan. 

Considering Pacific Rim, the most recent "kaiju" film, did $45 million opening and over $100 million total in China (assuming Godzilla should do similar) and Godzilla has home field advantage so to speak in Japan and should do well there it is safe to assume Godzilla could easily top $500 million total. 

Again not to shabby for a film that some critics felt would be a flop not even making it's production budget back.

From fxguide
When director Gareth Edwards began the task of tackling a new on-screen version of Godzilla, he looked to famed studio Weta Workshop to help flesh out initial designs. fxguide spoke to key Weta Workshop artists about their design process for the famous creature. Read there interview of the artists here.