Yep...they call it the transbay tube under the SF bay. The tunnel isn't completely under the earth though as it sits on the bottom of the bay...which means if you're in there during a big enough earthquake...well...you'll drown.
Currently it goes underwater twice. Once across the Bay from Oakland to SF which others have mentioned. It also goes under Lake Merritt in Oakland for a short distance.
In the coming years it will also go under Lake Elizabeth in Fremont. They are currently digging this tunnel as part of the Warm Springs extension.
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Yep...they call it the transbay tube under the SF bay. The tunnel isn't completely under the earth though as it sits on the bottom of the bay...which means if you're in there during a big enough earthquake...well...you'll drown.
Currently it goes underwater twice. Once across the Bay from Oakland to SF which others have mentioned. It also goes under Lake Merritt in Oakland for a short distance.
In the coming years it will also go under Lake Elizabeth in Fremont. They are currently digging this tunnel as part of the Warm Springs extension.
Yes. It goes under after the Embarcadero station for about five miles and comes up in Oakland.