The Bifrost (Rainbow Bridge)

The Bifrost was the bridge of the Gods and would only be visible to man when the sun shines among the rain, hence the nickname the Rainbow Bridge. It is hard to find the beginning of the bridge which was believed to lead mortals to the realm of the Gods. 

The bridge was believed to span not only the different realms but time itself; rarely being traveled by mortals as only the Gods had the power to locate the bridge and traverse the barriers separating our realms. It was believed that the God Heimdallr (A.K.A. Heimdall) was the keeper of the bridge and would not allow the unworthy to pass into Asgard (The realm of the Aesir)

(Image painted by Angela Hall)